{"id":18970,"date":"2025-08-08T16:46:32","date_gmt":"2025-08-08T08:46:32","guid":{"rendered":"https:\/\/92it.top\/?p=18970"},"modified":"2025-08-08T20:55:39","modified_gmt":"2025-08-08T12:55:39","slug":"mysql%e4%b8%ba%e4%bd%95%e9%92%9f%e7%88%b1b%e6%a0%91%e7%b4%a2%e5%bc%95%ef%bc%8c%e8%80%8c%e9%9d%9eb%e6%a0%91%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/92it.top\/?p=18970","title":{"rendered":"MySQL\u4e3a\u4f55\u949f\u7231B+\u6811\u7d22\u5f15\uff0c\u800c\u975eB\u6811\uff1f"},"content":{"rendered":"\n<p>\u8f6c\u8f7d\uff1a<a href=\"https:\/\/golangstar.cn\/backend_series\/advanced_interview\/database_index.html\">MySQL\u4e3a\u4f55\u949f\u7231B+\u6811\u7d22\u5f15\uff0c\u800c\u975eB\u6811\uff1f<\/a><\/p>\n\n\n\n<p>\u4eca\u5929\uff0c\u6211\u4eec\u6765\u7cfb\u7edf\u6027\u5730\u804a\u804a\u6570\u636e\u5e93\u8fd9\u4e2a\u8bdd\u9898\u3002\u5728\u4efb\u4f55\u4e00\u4e2a\u540e\u7aef\u5de5\u7a0b\u5e08\u7684\u804c\u4e1a\u751f\u6daf\u4e2d\uff0c\u6570\u636e\u5e93\u8bbe\u8ba1\u548cSQL\u4f18\u5316\u7684\u80fd\u529b\uff0c\u90fd\u76f4\u63a5\u51b3\u5b9a\u4e86\u4f60\u6240\u6784\u5efa\u7cfb\u7edf\u7684\u6027\u80fd\u4e0a\u9650\u3002\u65e0\u8bba\u516c\u53f8\u89c4\u6a21\u5927\u5c0f\uff0c\u6570\u636e\u5e93\u90fd\u662f\u6280\u672f\u6808\u4e2d\u4e0d\u53ef\u6216\u7f3a\u7684\u4e00\u73af\u3002\u56e0\u6b64\uff0c\u5373\u4fbf\u4f60\u7f3a\u4e4f\u5fae\u670d\u52a1\u76f8\u5173\u7684\u7ecf\u9a8c\uff0c\u624e\u5b9e\u7684\u6570\u636e\u5e93\u529f\u5e95\u4e5f\u5b8c\u5168\u53ef\u4ee5\u6210\u4e3a\u4f60\u9762\u8bd5\u4e2d\u7684\u81f4\u80dc\u6cd5\u5b9d\u3002<\/p>\n\n\n\n<p>\u4eca\u5929\uff0c\u6211\u4eec\u5c31\u4ece\u6570\u636e\u5e93\u7684\u5fc3\u810f\u2014\u2014\u7d22\u5f15\uff0c\u5f00\u59cb\u6211\u4eec\u7684\u7b2c\u4e00\u8bb2\u3002<\/p>\n\n\n\n<p>\u7d22\u5f15\u662f\u9762\u8bd5\u4e2d\u7684\u9ad8\u9891\u8003\u70b9\uff0c\u4f46\u5f88\u591a\u540c\u5b66\u7684\u56de\u7b54\u5f80\u5f80\u6d41\u4e8e\u8868\u9762\uff0c\u50cf\u662f\u80cc\u8bf5\u6559\u79d1\u4e66\uff0c\u5f88\u96be\u7ed9\u9762\u8bd5\u5b98\u7559\u4e0b\u6df1\u523b\u7684\u5370\u8c61\u3002\u5b9e\u9645\u4e0a\uff0c\u7d22\u5f15\u662f\u4e00\u4e2a\u7406\u8bba\u4e0e\u5b9e\u8df5\u7d27\u5bc6\u7ed3\u5408\u7684\u9886\u57df\u3002\u5728\u8fd9\u7bc7\u6587\u7ae0\u91cc\uff0c\u6211\u4f1a\u5148\u5e26\u4f60\u5f7b\u5e95\u641e\u61c2\u7d22\u5f15\u7684\u5e95\u5c42\u539f\u7406\uff1b\u5728\u540e\u7eed\u7684\u6587\u7ae0\u4e2d\uff0c\u6211\u4eec\u518d\u7ed3\u5408SQL\u4f18\u5316\uff0c\u6df1\u5165\u63a2\u8ba8\u7d22\u5f15\u8bbe\u8ba1\u7684\u5b9e\u6218\u6280\u5de7\u3002<\/p>\n\n\n\n<p>\u7d22\u5f15\u7684\u77e5\u8bc6\u70b9\u786e\u5b9e\u4e0d\u5c11\uff0c\u800c\u4e14\u5f88\u591a\u7ec6\u8282\u96f6\u6563\u3001\u4e0d\u6210\u4f53\u7cfb\uff0c\u8bb0\u5fc6\u8d77\u6765\u9887\u6709\u96be\u5ea6\u3002\u522b\u62c5\u5fc3\uff0c\u6211\u4f1a\u7528\u6700\u76f4\u767d\u7684\u8bed\u8a00\u548c\u4e00\u4e9b\u5de7\u5999\u7684\u7c7b\u6bd4\uff0c\u5e2e\u52a9\u4f60\u6784\u5efa\u8d77\u5173\u4e8e\u7d22\u5f15\u7684\u5b8c\u6574\u77e5\u8bc6\u56fe\u8c31\u3002<\/p>\n\n\n\n<p>\u3000<\/p>\n\n\n\n<p><strong>1. \u7d22\u5f15\u7684\u57fa\u7840\u77e5\u8bc6<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>\u9996\u5148\uff0c\u6211\u4eec\u8981\u660e\u786e\u4e00\u4e2a\u6982\u5ff5\uff1a\u7d22\u5f15\u662f\u4e00\u79cd\u7528\u4e8e\u52a0\u901f\u6570\u636e\u68c0\u7d22\u7684\u7279\u6b8a\u6570\u636e\u7ed3\u6784\u3002\u51e0\u4e4e\u6240\u6709\u6d89\u53ca\u5b58\u50a8\u548c\u67e5\u627e\u7684\u7cfb\u7edf\u7ec4\u4ef6\uff0c\u80cc\u540e\u90fd\u6709\u7d22\u5f15\u7684\u8eab\u5f71\uff0c\u5c3d\u7ba1\u5b83\u4eec\u7684\u5b9e\u73b0\u539f\u7406\u5404\u4e0d\u76f8\u540c\u3002<\/p>\n\n\n\n<p>\u8981\u7406\u89e3MySQL\u7684\u7d22\u5f15\uff0c\u6211\u4eec\u5fc5\u987b\u5148\u4eceB+\u6811\u5f00\u59cb\u3002<\/p>\n\n\n\n<p><strong>1.1 B+\u6811\uff1a\u7d22\u5f15\u7684\u9aa8\u67b6<\/strong><\/p>\n\n\n\n<p>B+\u6811\u662f\u4e00\u79cd\u7cbe\u5de7\u7684\u591a\u53c9\u6811\u7ed3\u6784\u3002\u5bf9\u4e8e\u4e00\u68f5m\u9636\u7684B+\u6811\uff0c\u5b83\u9075\u5faa\u4ee5\u4e0b\u89c4\u5219\uff1a<\/p>\n\n\n\n<ol>\n<li>\u6811\u4e2d\u7684\u6bcf\u4e2a\u8282\u70b9\u6700\u591a\u53ef\u4ee5\u62e5\u6709m\u4e2a\u5b50\u8282\u70b9\u3002<\/li>\n\n\n\n<li>\u9664\u4e86\u6839\u8282\u70b9\uff0c\u5176\u4ed6\u6bcf\u4e2a\u8282\u70b9\u81f3\u5c11\u6709 <code>\u2308m\/2\u2309<\/code> \u4e2a\u5b50\u8282\u70b9\u3002\u6839\u8282\u70b9\u82e5\u975e\u53f6\u5b50\uff0c\u5219\u81f3\u5c11\u6709\u4e24\u4e2a\u5b50\u8282\u70b9\u3002<\/li>\n\n\n\n<li>\u62e5\u6709k\u4e2a\u5b50\u8282\u70b9\u7684\u975e\u53f6\u5b50\u8282\u70b9\uff0c\u5fc5\u5b9a\u5305\u542bk\u4e2a\u5173\u952e\u5b57\uff08\u53ef\u4ee5\u7406\u89e3\u4e3a\u7d22\u5f15\u5217\u7684\u503c\uff09\u3002<\/li>\n<\/ol>\n\n\n\n<p>\u5b9a\u4e49\u53ef\u80fd\u6709\u4e9b\u67af\u71e5\uff0c\u8bb0\u4e0d\u4f4f\u6ca1\u5173\u7cfb\uff0c\u4f46\u4e0b\u9762\u8fd9\u4e24\u4e2a\u6838\u5fc3\u7279\u5f81\uff0c\u4f60\u5fc5\u987b\u7262\u7262\u8bb0\u4f4f\uff1a<\/p>\n\n\n\n<ul>\n<li><strong>\u6570\u636e\u53ea\u5b58\u5728\u4e8e\u53f6\u5b50\u8282\u70b9<\/strong>\uff1a\u6240\u6709\u975e\u53f6\u5b50\u8282\u70b9\uff08\u53ef\u4ee5\u770b\u4f5c\u662f\u201c\u76ee\u5f55\u9875\u201d\uff09\u4ec5\u5b58\u50a8\u5173\u952e\u5b57\u4fe1\u606f\uff0c\u7528\u4e8e\u6307\u5f15\u67e5\u627e\u65b9\u5411\u3002\u771f\u6b63\u7684\u6570\u636e\u8bb0\u5f55\uff0c\u5168\u90e8\u5b58\u653e\u5728\u6811\u6700\u5e95\u5c42\u7684\u53f6\u5b50\u8282\u70b9\u4e2d\u3002<\/li>\n\n\n\n<li><strong>\u53f6\u5b50\u8282\u70b9\u6784\u6210\u6709\u5e8f\u94fe\u8868<\/strong>\uff1a\u6240\u6709\u7684\u53f6\u5b50\u8282\u70b9\u901a\u8fc7\u6307\u9488\u4e32\u8054\u5728\u4e00\u8d77\uff0c\u5f62\u6210\u4e00\u4e2a\u6709\u5e8f\u7684\u53cc\u5411\u94fe\u8868\u3002<\/li>\n<\/ul>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"370\" src=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-250-1024x370.png\" alt=\"\" class=\"wp-image-18971\" style=\"width:558px;height:auto\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-250-1024x370.png 1024w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-250-300x109.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-250-768x278.png 768w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-250-830x300.png 830w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-250-230x83.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-250-350x127.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-250-480x174.png 480w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-250.png 1266w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure><\/div>\n\n\n<p><p>\u4e3a\u4e86\u5e2e\u4f60\u66f4\u597d\u5730\u7406\u89e3\uff0c\u6211\u4eec\u53ef\u4ee5\u628a\u4e00\u68f5B+\u6811\u60f3\u8c61\u6210\u4e00\u90e8\u7cbe\u5fc3\u7f16\u6392\u7684\u5b57\u5178\u3002\u975e\u53f6\u5b50\u8282\u70b9\u5c31\u50cf\u662f\u5b57\u5178\u7684\u201c\u90e8\u9996\u76ee\u5f55\u201d\u6216\u201c\u62fc\u97f3\u7d22\u5f15\u201d\uff0c\u5b83\u4eec\u672c\u8eab\u4e0d\u89e3\u91ca\u5b57\u7684\u542b\u4e49\uff08\u4e0d\u5b58\u6570\u636e\uff09\uff0c\u53ea\u544a\u8bc9\u4f60\u67d0\u4e2a\u5b57\u53ef\u80fd\u5728\u54ea\u4e9b\u9875\u7801\u8303\u56f4\u91cc\u3002\u800c\u53f6\u5b50\u8282\u70b9\uff0c\u5c31\u662f\u5b57\u5178\u7684\u6b63\u6587\u90e8\u5206\uff0c\u5305\u542b\u4e86\u6bcf\u4e2a\u5b57\u7684\u8be6\u7ec6\u91ca\u4e49\uff08\u5b58\u50a8\u771f\u5b9e\u6570\u636e\uff09\uff0c\u5e76\u4e14\u8fd9\u4e9b\u6b63\u6587\u9875\u7801\u662f\u8fde\u7eed\u7684\uff08\u94fe\u8868\u4e32\u8054\uff09\uff0c\u65b9\u4fbf\u4f60\u6309\u987a\u5e8f\u7ffb\u9605\u3002<\/p><p>\u6b63\u662f\u8fd9\u4e9b\u7279\u6027\uff0c\u4f7f\u5f97B+\u6811\u6210\u4e3a\u6570\u636e\u5e93\u7d22\u5f15\u7684\u7edd\u4f73\u9009\u62e9\uff0c\u5b83\u4e3b\u8981\u6709\u4e09\u5927\u4f18\u52bf\uff1a<\/p><ol><li><p><strong>\u67e5\u8be2\u6027\u80fd\u7a33\u5b9a\u9ad8\u6548<\/strong>\uff1a\u76f8\u6bd4\u4e8e\u4e8c\u53c9\u6811\uff0cB+\u6811\u66f4\u52a0\u201c\u77ee\u80d6\u201d\u3002\u6811\u7684\u9ad8\u5ea6\u76f4\u63a5\u5f71\u54cdI\/O\u6b21\u6570\uff0c\u66f4\u4f4e\u7684\u9ad8\u5ea6\u610f\u5473\u7740\u66f4\u5c11\u7684\u78c1\u76d8\u8bfb\u53d6\uff0c\u67e5\u8be2\u6027\u80fd\u81ea\u7136\u66f4\u597d\u3002<\/p><\/li><li><p><strong>\u5929\u7136\u9002\u5408\u8303\u56f4\u67e5\u8be2<\/strong>\uff1a\u7531\u4e8e\u53f6\u5b50\u8282\u70b9\u662f\u4e32\u8054\u8d77\u6765\u7684\u6709\u5e8f\u94fe\u8868\uff0c\u5f53\u9700\u8981\u8fdb\u884c\u8303\u56f4\u67e5\u627e\uff08\u4f8b\u5982 <code>WHERE id > 100<\/code>\uff09\u65f6\uff0c\u53ea\u9700\u5728B+\u6811\u4e2d\u5b9a\u4f4d\u5230\u8303\u56f4\u7684\u8d77\u59cb\u70b9\uff0c\u7136\u540e\u6cbf\u7740\u53f6\u5b50\u8282\u70b9\u7684\u94fe\u8868\u987a\u5e8f\u904d\u5386\u5373\u53ef\uff0c\u6548\u7387\u6781\u9ad8\u3002<\/p><\/li><li><p><strong>\u5185\u5b58\u5229\u7528\u7387\u66f4\u9ad8<\/strong>\uff1a\u56e0\u4e3a\u975e\u53f6\u5b50\u8282\u70b9\u4e0d\u5b58\u50a8\u6570\u636e\uff0c\u53ea\u5b58\u50a8\u5173\u952e\u5b57\u548c\u6307\u9488\uff0c\u6240\u4ee5\u5355\u4e2a\u8282\u70b9\u53ef\u4ee5\u5bb9\u7eb3\u66f4\u591a\u7684\u5173\u952e\u5b57\u3002\u8fd9\u610f\u5473\u7740\uff0c\u5728\u5185\u5b58\u6709\u9650\u7684\u60c5\u51b5\u4e0b\uff0c\u6211\u4eec\u53ef\u4ee5\u5c06\u6574\u68f5\u6811\u7684\u975e\u53f6\u5b50\u8282\u70b9\uff08\u5373\u7d22\u5f15\u7684\u201c\u76ee\u5f55\u90e8\u5206\u201d\uff09\u5168\u90e8\u52a0\u8f7d\u5230\u5185\u5b58\u4e2d\uff0c\u5927\u5927\u51cf\u5c11\u4e86\u8bbf\u95ee\u7d22\u5f15\u65f6\u7684\u78c1\u76d8I\/O\u3002<\/p><\/li><\/ol><p>\u5f88\u591a\u4eba\u80fd\u8bb0\u4f4f\u524d\u4e24\u4e2a\u4f18\u70b9\uff0c\u5374\u5e38\u5e38\u5ffd\u7565\u7b2c\u4e09\u70b9\u3002\u5b9e\u9645\u4e0a\uff0c\u6211\u4eec\u8ba8\u8bba\u7d22\u5f15\u63d0\u5347\u67e5\u8be2\u6027\u80fd\u65f6\uff0c\u6709\u4e00\u4e2a\u9690\u542b\u7684\u5927\u524d\u63d0\uff1a<strong>\u7d22\u5f15\u672c\u8eab\uff08\u81f3\u5c11\u662f\u9ad8\u9891\u8bbf\u95ee\u7684\u975e\u53f6\u5b50\u8282\u70b9\uff09\u662f\u5e38\u9a7b\u5185\u5b58\u7684<\/strong>\uff0c\u800c\u771f\u6b63\u7684\u6570\u636e\u884c\u5219\u5b58\u653e\u5728\u78c1\u76d8\u4e0a\u3002\u5982\u679c\u7d22\u5f15\u4e5f\u9700\u8981\u9891\u7e41\u4ece\u78c1\u76d8\u8bfb\u53d6\uff0c\u90a3\u5b83\u7684\u52a0\u901f\u6548\u679c\u5c06\u5927\u6253\u6298\u6263\u3002<\/p><a href=\"https:\/\/golangstar.cn\/backend_series\/advanced_interview\/database_index.html#_1-1-b-\u6811-\u7d22\u5f15\u7684\u9aa8\u67b6\"><\/a><\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"530\" src=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-251-1024x530.png\" alt=\"\" class=\"wp-image-18972\" style=\"width:464px;height:auto\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-251-1024x530.png 1024w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-251-300x155.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-251-768x397.png 768w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-251-830x429.png 830w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-251-230x119.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-251-350x181.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-251-480x248.png 480w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-251.png 1268w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure><\/div>\n\n\n<p><strong><a href=\"https:\/\/golangstar.cn\/backend_series\/advanced_interview\/database_index.html#_1-\u7d22\u5f15\u7684\u57fa\u7840\u77e5\u8bc6\"><\/a>1.2 \u591a\u7ef4\u89c6\u89d2\u4e0b\u7684\u7d22\u5f15\u5206\u7c7b<a href=\"https:\/\/golangstar.cn\/backend_series\/advanced_interview\/database_index.html#_1-\u7d22\u5f15\u7684\u57fa\u7840\u77e5\u8bc6\"><\/a><\/strong><\/p>\n\n\n\n<p>\u5728MySQL\u4e2d\uff0c\u7d22\u5f15\u7684\u53eb\u6cd5\u5f88\u591a\uff0c\u8fd9\u662f\u56e0\u4e3a\u6211\u4eec\u53ef\u4ee5\u4ece\u4e0d\u540c\u7684\u7ef4\u5ea6\u53bb\u5ba1\u89c6\u548c\u5212\u5206\u5b83\u3002\u540c\u4e00\u4e2a\u7d22\u5f15\uff0c\u53ef\u80fd\u540c\u65f6\u62e5\u6709\u591a\u4e2a\u8eab\u4efd\u3002<\/p>\n\n\n\n<ul>\n<li><strong>\u805a\u7c07\u7d22\u5f15 (Clustered Index) vs. \u975e\u805a\u7c07\u7d22\u5f15 (Non-Clustered Index)<\/strong>\uff1a\u8fd9\u662f\u4ece\u6570\u636e\u5b58\u50a8\u65b9\u5f0f\u7684\u89d2\u5ea6\u6765\u5212\u5206\u7684\u3002<\/li>\n\n\n\n<li><strong>\u8986\u76d6\u7d22\u5f15 (Covering Index)<\/strong>\uff1a\u4ece\u67e5\u8be2\u8fc7\u7a0b\u7684\u89d2\u5ea6\u6765\u770b\uff0c\u5982\u679c\u4e00\u4e2a\u7d22\u5f15\u5305\u542b\u4e86\u67e5\u8be2\u6240\u9700\u7684\u6240\u6709\u5217\uff0c\u5b83\u5c31\u662f\u8986\u76d6\u7d22\u5f15\u3002<\/li>\n\n\n\n<li><strong>\u552f\u4e00\u7d22\u5f15 (Unique Index)<\/strong>\uff1a\u4ece\u7ea6\u675f\u6027\u7684\u89d2\u5ea6\u6765\u770b\uff0c\u7d22\u5f15\u5217\u7684\u503c\u5fc5\u987b\u662f\u552f\u4e00\u7684\u3002<\/li>\n\n\n\n<li><strong>\u524d\u7f00\u7d22\u5f15 (Prefix Index)<\/strong>\uff1a\u4ece\u7d22\u5f15\u5185\u5bb9\u7684\u89d2\u5ea6\u6765\u770b\uff0c\u53ea\u7d22\u5f15\u4e86\u67d0\u4e2a\u5217\u503c\u7684\u524d\u4e00\u90e8\u5206\u5b57\u7b26\u3002\u6bd4\u5982\uff0c\u5728\u4e00\u4e2a <code>varchar(255)<\/code> \u7684\u5217\u4e0a\uff0c\u53ea\u53d6\u524d50\u4e2a\u5b57\u7b26\u6765\u521b\u5efa\u7d22\u5f15\u3002<\/li>\n\n\n\n<li><strong>\u7ec4\u5408\u7d22\u5f15 (Composite Index)<\/strong>\uff1a\u4e5f\u53eb\u8054\u5408\u7d22\u5f15\uff0c\u6307\u7531\u591a\u4e2a\u5217\u5171\u540c\u7ec4\u6210\u7684\u7d22\u5f15\u3002<\/li>\n\n\n\n<li><strong>\u5168\u6587\u7d22\u5f15 (Full-Text Index)<\/strong>\uff1a\u4e13\u95e8\u7528\u4e8e\u652f\u6301\u6587\u672c\u5185\u5bb9\u7684\u6a21\u7cca\u641c\u7d22\u3002<\/li>\n\n\n\n<li><strong>\u54c8\u5e0c\u7d22\u5f15 (Hash Index)<\/strong>\uff1a\u57fa\u4e8e\u54c8\u5e0c\u8868\u5b9e\u73b0\u7684\u7d22\u5f15\uff0c\u67e5\u8be2\u6027\u80fd\u6781\u9ad8\uff0c\u4f46\u4e0d\u652f\u6301\u8303\u56f4\u67e5\u8be2\u3002MySQL\u7684InnoDB\u5b58\u50a8\u5f15\u64ce\u9ed8\u8ba4\u4e0d\u652f\u6301\u663e\u5f0f\u521b\u5efa\u54c8\u5e0c\u7d22\u5f15\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u7406\u89e3\u8fd9\u4e9b\u5206\u7c7b\u7684\u5173\u952e\u5728\u4e8e\uff0c\u4e0d\u8981\u628a\u5b83\u4eec\u770b\u4f5c\u662f\u4e92\u65a5\u7684\u3002\u4e00\u4e2a\u7531 <code>(name, age)<\/code> \u4e24\u5217\u7ec4\u6210\u7684\u552f\u4e00\u7d22\u5f15\uff0c\u5f53\u7528\u4e8e\u67e5\u8be2 <code>SELECT name, age FROM ...<\/code> \u65f6\uff0c\u5b83\u540c\u65f6\u4e5f\u662f\u4e00\u4e2a\u7ec4\u5408\u7d22\u5f15\u3001\u552f\u4e00\u7d22\u5f15\u548c\u8986\u76d6\u7d22\u5f15\u3002<\/p>\n\n\n\n<p><strong>1.3 \u805a\u7c07\u7d22\u5f15\u4e0e\u975e\u805a\u7c07\u7d22\u5f15<\/strong><\/p>\n\n\n\n<p>\u8fd9\u662f\u7d22\u5f15\u5206\u7c7b\u4e2d\u6700\u6838\u5fc3\u3001\u4e5f\u6700\u9700\u8981\u7406\u89e3\u900f\u5f7b\u7684\u4e00\u5bf9\u6982\u5ff5\u3002\u5b83\u4eec\u7684\u552f\u4e00\u533a\u522b\u5728\u4e8e<strong>\u53f6\u5b50\u8282\u70b9\u5b58\u653e\u7684\u5185\u5bb9\u4e0d\u540c<\/strong>\u3002<\/p>\n\n\n\n<ul>\n<li><strong>\u805a\u7c07\u7d22\u5f15<\/strong>\uff1a\u5176\u53f6\u5b50\u8282\u70b9\u76f4\u63a5\u5b58\u50a8\u4e86\u5b8c\u6574\u7684<strong>\u6570\u636e\u884c<\/strong>\u3002\u5728InnoDB\u4e2d\uff0c\u6570\u636e\u8868\u672c\u8eab\u5c31\u662f\u6309\u4e3b\u952e\u7ec4\u7ec7\u7684\u4e00\u68f5B+\u6811\uff0c\u8fd9\u68f5\u6811\u5c31\u662f\u805a\u7c07\u7d22\u5f15\u3002\u56e0\u6b64\uff0c\u4e00\u5f20\u8868\u53ea\u80fd\u6709\u4e00\u4e2a\u805a\u7c07\u7d22\u5f15\u3002<\/li>\n\n\n\n<li><strong>\u975e\u805a\u7c07\u7d22\u5f15<\/strong>\uff08\u4e5f\u53eb\u4e8c\u7ea7\u7d22\u5f15\u6216\u8f85\u52a9\u7d22\u5f15\uff09\uff1a\u5176\u53f6\u5b50\u8282\u70b9\u5b58\u50a8\u7684\u4e0d\u662f\u6570\u636e\u884c\uff0c\u800c\u662f\u8be5\u884c\u6570\u636e\u5bf9\u5e94\u7684<strong>\u4e3b\u952e\u503c<\/strong>\u3002<\/li>\n<\/ul>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"651\" src=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-252-1024x651.png\" alt=\"\" class=\"wp-image-18973\" style=\"width:490px;height:auto\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-252-1024x651.png 1024w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-252-300x191.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-252-768x488.png 768w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-252-830x528.png 830w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-252-230x146.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-252-350x223.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-252-480x305.png 480w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-252.png 1302w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure><\/div>\n\n\n<p>\u6709\u4e86\u8fd9\u4e2a\u533a\u5206\uff0c\u6211\u4eec\u5c31\u80fd\u8f7b\u677e\u7406\u89e3\u201c\u56de\u8868\u201d\u8fd9\u4e2a\u6982\u5ff5\u4e86\u3002\u5f53\u4f60\u4f7f\u7528\u4e00\u4e2a\u975e\u805a\u7c07\u7d22\u5f15\u8fdb\u884c\u67e5\u8be2\u65f6\uff0c\u6570\u636e\u5e93\u7684\u6267\u884c\u6d41\u7a0b\u662f\u8fd9\u6837\u7684\uff1a<\/p>\n\n\n\n<ol>\n<li>\u9996\u5148\u5728\u975e\u805a\u7c07\u7d22\u5f15\u7684B+\u6811\u4e2d\uff0c\u6839\u636e\u4f60\u7684\u67e5\u8be2\u6761\u4ef6\u4e00\u8def\u627e\u5230\u5bf9\u5e94\u7684\u53f6\u5b50\u8282\u70b9\u3002<\/li>\n\n\n\n<li>\u4ece\u8be5\u53f6\u5b50\u8282\u70b9\u4e2d\uff0c\u83b7\u53d6\u5230\u6570\u636e\u884c\u7684<strong>\u4e3b\u952e\u503c<\/strong>\u3002<\/li>\n\n\n\n<li>\u62ff\u7740\u8fd9\u4e2a\u4e3b\u952e\u503c\uff0c\u518d\u56de\u5230\u805a\u7c07\u7d22\u5f15\uff08\u4e5f\u5c31\u662f\u4e3b\u952e\u7d22\u5f15\uff09\u7684B+\u6811\u4e2d\uff0c\u91cd\u65b0\u67e5\u627e\u4e00\u6b21\uff0c\u6700\u7ec8\u5b9a\u4f4d\u5230\u53f6\u5b50\u8282\u70b9\uff0c\u8bfb\u53d6\u5b8c\u6574\u7684\u884c\u6570\u636e\u3002<\/li>\n<\/ol>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"683\" src=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-253-1024x683.png\" alt=\"\" class=\"wp-image-18974\" style=\"width:516px;height:auto\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-253-1024x683.png 1024w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-253-300x200.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-253-768x512.png 768w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-253-830x554.png 830w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-253-230x153.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-253-350x234.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-253-480x320.png 480w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-253.png 1268w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure><\/div>\n\n\n<p>\u8fd9\u4e2a\u201c\u62ff\u7740\u4e3b\u952e\u518d\u67e5\u4e00\u6b21\u201d\u7684\u8fc7\u7a0b\uff0c\u5c31\u53eb\u505a<strong>\u56de\u8868 (Lookup)<\/strong>\u3002\u5982\u56fe\u6240\u793a\uff0c\u67e5\u8be2\u5148\u6cbf\u7740\u7eff\u8272\u8def\u5f84\u5728\u975e\u805a\u7c07\u7d22\u5f15\u4e2d\u627e\u5230\u4e3b\u952e\uff0c\u7136\u540e\u518d\u6cbf\u7740\u9ec4\u8272\u8def\u5f84\u53bb\u805a\u7c07\u7d22\u5f15\u4e2d\u627e\u5230\u5b8c\u6574\u7684\u884c\u6570\u636e\u3002\u7531\u4e8e\u8fd9\u4e2a\u8fc7\u7a0b\u591a\u4e86\u4e00\u6b21B+\u6811\u7684\u67e5\u627e\uff0c\u5e76\u4e14\u5f88\u53ef\u80fd\u89e6\u53d1\u989d\u5916\u7684\u78c1\u76d8I\/O\uff0c\u6240\u4ee5\u56de\u8868\u7684\u6027\u80fd\u5f00\u9500\u8f83\u5927\u3002\u5728\u5b9e\u9645\u7684SQL\u4f18\u5316\u4e2d\uff0c<strong>\u907f\u514d\u4e0d\u5fc5\u8981\u7684\u56de\u8868<\/strong>\u662f\u4e00\u4e2a\u6838\u5fc3\u539f\u5219\u3002<\/p>\n\n\n\n<p><strong>1.4 \u8986\u76d6\u7d22\u5f15\uff1a\u907f\u514d\u56de\u8868\u7684\u5229\u5668<\/strong><\/p>\n\n\n\n<p>\u5982\u4f55\u907f\u514d\u56de\u8868\u5462\uff1f\u7b54\u6848\u5c31\u662f\u4f7f\u7528<strong>\u8986\u76d6\u7d22\u5f15<\/strong>\u3002<\/p>\n\n\n\n<p>\u5f53\u4e00\u4e2a\u67e5\u8be2\u6240\u9700\u8981\u8fd4\u56de\u7684\u5217\uff0c\u6070\u597d\u90fd\u5b58\u5728\u4e8e\u4f60\u6240\u4f7f\u7528\u7684\u90a3\u4e2a\u7d22\u5f15\u4e2d\u65f6\uff0c\u6570\u636e\u5e93\u5c31\u65e0\u9700\u518d\u56de\u5230\u4e3b\u952e\u7d22\u5f15\u53bb\u67e5\u627e\u5b8c\u6574\u7684\u884c\u6570\u636e\u4e86\u3002\u5b83\u53ef\u4ee5\u76f4\u63a5\u4ece\u5f53\u524d\u8fd9\u4e2a\u975e\u805a\u7c07\u7d22\u5f15\u7684\u53f6\u5b50\u8282\u70b9\u4e2d\u63d0\u53d6\u51fa\u6240\u6709\u9700\u8981\u7684\u503c\u5e76\u8fd4\u56de\u3002\u6b64\u65f6\uff0c\u8fd9\u4e2a\u7d22\u5f15\u5bf9\u4e8e\u8be5\u67e5\u8be2\u800c\u8a00\uff0c\u5c31\u662f\u4e00\u4e2a\u8986\u76d6\u7d22\u5f15\u3002<\/p>\n\n\n\n<p>\u4e3e\u4e2a\u4f8b\u5b50\uff0c\u5047\u8bbe\u6211\u4eec\u6709\u4e00\u4e2a\u7528\u6237\u8868 <code>user_tab<\/code>\uff0c\u5e76\u5728 <code>(id, name)<\/code> \u8fd9\u4e24\u5217\u4e0a\u521b\u5efa\u4e86\u4e00\u4e2a\u7ec4\u5408\u7d22\u5f15\u3002\u5bf9\u4e8e\u4e0b\u9762\u8fd9\u4e2a\u67e5\u8be2\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">SELECT id, name FROM user_tab WHERE id = 50;<\/pre>\n\n\n\n<p>\u7531\u4e8e\u67e5\u8be2\u8bf7\u6c42\u7684 <code>id<\/code> \u548c <code>name<\/code> \u4e24\u5217\u90fd\u5df2\u7ecf\u5305\u542b\u5728\u6211\u4eec\u7684\u7ec4\u5408\u7d22\u5f15\u4e2d\u4e86\uff0c\u6570\u636e\u5e93\u53ef\u4ee5\u76f4\u63a5\u4ece\u8fd9\u4e2a\u7d22\u5f15\u6811\u4e2d\u83b7\u53d6\u6570\u636e\u5e76\u8fd4\u56de\uff0c\u5b8c\u5168\u4e0d\u9700\u8981\u56de\u8868\u64cd\u4f5c\u3002<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"472\" src=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-254-1024x472.png\" alt=\"\" class=\"wp-image-18975\" style=\"width:490px;height:auto\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-254-1024x472.png 1024w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-254-300x138.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-254-768x354.png 768w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-254-830x383.png 830w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-254-230x106.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-254-350x161.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-254-480x221.png 480w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-254.png 1270w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure><\/div>\n\n\n<p>\u56e0\u6b64\uff0c\u201c\u8986\u76d6\u7d22\u5f15\u201d\u4e0d\u662f\u4e00\u79cd\u7d22\u5f15\u7c7b\u578b\uff0c\u800c\u662f\u7d22\u5f15\u76f8\u5bf9\u4e8e\u67d0\u4e2a\u7279\u5b9a\u67e5\u8be2\u7684\u4e00\u79cd\u201c\u72b6\u6001\u201d\u6216\u201c\u80fd\u529b\u201d\u3002\u8fd9\u4e5f\u5f15\u51fa\u4e86SQL\u4f18\u5316\u4e2d\u4e24\u6761\u9ec4\u91d1\u6cd5\u5219\uff1a<\/p>\n\n\n\n<ol>\n<li><strong>\u53ea\u67e5\u8be2\u4f60\u9700\u8981\u7684\u5217<\/strong>\uff0c\u575a\u51b3\u907f\u514d <code>SELECT *<\/code>\uff0c\u8fd9\u80fd\u589e\u52a0\u547d\u4e2d\u8986\u76d6\u7d22\u5f15\u7684\u6982\u7387\u3002<\/li>\n\n\n\n<li><strong>\u4e3a\u9ad8\u9891\u67e5\u8be2\u573a\u666f\u8bbe\u8ba1\u4e13\u95e8\u7684\u8986\u76d6\u7d22\u5f15<\/strong>\uff0c\u5c06\u67e5\u8be2\u3001\u7b5b\u9009\u3001\u8fd4\u56de\u7684\u5217\u90fd\u5305\u542b\u8fdb\u53bb\u3002<\/li>\n<\/ol>\n\n\n\n<p>\u8fd9\u4e24\u6761\u6cd5\u5219\u7684\u672c\u8d28\uff0c\u90fd\u662f\u4e3a\u4e86\u5c3d\u53ef\u80fd\u5730\u51cf\u5c11\u56de\u8868\uff0c\u4ece\u800c\u63d0\u5347\u67e5\u8be2\u6548\u7387\u3002<\/p>\n\n\n\n<p><strong>1.5 \u6700\u5de6\u5339\u914d\u539f\u5219<a href=\"https:\/\/golangstar.cn\/backend_series\/advanced_interview\/database_index.html#_1-5-\u6700\u5de6\u5339\u914d\u539f\u5219\"><\/a><\/strong><\/p>\n\n\n\n<p>\u5f53\u6211\u4eec\u5728\u591a\u4e2a\u5217\u4e0a\u521b\u5efa\u7ec4\u5408\u7d22\u5f15\u65f6\uff0c\u4f8b\u5982 <code>&lt;A, B, C&gt;<\/code>\uff0c\u7d22\u5f15\u7684\u67e5\u8be2\u548c\u5339\u914d\u9075\u5faa\u7740\u4e25\u683c\u7684\u201c\u6700\u5de6\u5339\u914d\u539f\u5219\u201d\u3002\u8981\u7406\u89e3\u8fd9\u4e2a\u539f\u5219\uff0c\u6211\u4eec\u5fc5\u987b\u5148\u7406\u89e3\u7ec4\u5408\u7d22\u5f15\u7684\u6392\u5e8f\u65b9\u5f0f\u3002<\/p>\n\n\n\n<p>\u5728\u4e00\u4e2a <code>&lt;A, B, C&gt;<\/code> \u7684\u7ec4\u5408\u7d22\u5f15\u4e2d\uff0c\u6570\u636e\u662f\u8fd9\u6837\u6392\u5e8f\u7684\uff1a<\/p>\n\n\n\n<ul>\n<li>\u9996\u5148\uff0c\u6574\u4f53\u4e0a\u6309\u7167\u5217 A \u8fdb\u884c\u6392\u5e8f\u3002<\/li>\n\n\n\n<li>\u5728\u5217 A \u7684\u503c\u76f8\u540c\u7684\u60c5\u51b5\u4e0b\uff0c\u518d\u6309\u7167\u5217 B \u8fdb\u884c\u6392\u5e8f\u3002<\/li>\n\n\n\n<li>\u5728\u5217 A \u548c B \u7684\u503c\u90fd\u76f8\u540c\u7684\u60c5\u51b5\u4e0b\uff0c\u6700\u540e\u624d\u6309\u7167\u5217 C \u8fdb\u884c\u6392\u5e8f\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u8fd9\u610f\u5473\u7740\uff1a\u5217A\u662f\u7edd\u5bf9\u6709\u5e8f\u7684\uff1b\u53ea\u6709\u5728A\u786e\u5b9a\u7684\u524d\u63d0\u4e0b\uff0cB\u624d\u662f\u6709\u5e8f\u7684\uff1b\u53ea\u6709\u5728A\u548cB\u90fd\u786e\u5b9a\u7684\u524d\u63d0\u4e0b\uff0cC\u624d\u662f\u6709\u5e8f\u7684\u3002<\/p>\n\n\n\n<p>\u57fa\u4e8e\u8fd9\u4e2a\u6392\u5e8f\u89c4\u5219\uff0c\u6211\u4eec\u5c31\u80fd\u63a8\u65ad\u51fa\u7d22\u5f15\u7684\u4f7f\u7528\u60c5\u51b5\u4e86\u3002\u6211\u4eec\u53ef\u4ee5\u628a\u4e00\u6b21 <code>WHERE A=a1 AND B=b1 AND C=c1<\/code> \u7684\u67e5\u8be2\uff0c\u60f3\u8c61\u6210\u4e00\u4e2a\u5d4c\u5957\u5faa\u73af\u7684\u67e5\u627e\u8fc7\u7a0b\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ \u4f2a\u4ee3\u7801\u6f14\u793a WHERE A=a1 AND B=b1 AND C=c1 \u7684\u67e5\u627e\u8fc7\u7a0b\nfor a in sorted_A {\n    \/\/ \u7b2c\u4e00\u6b65\uff1a\u5728\u6709\u5e8f\u7684A\u5217\u4e2d\u5b9a\u4f4da1\n    if a == a1 {\n        for b in sorted_B_within_a1 {\n            \/\/ \u7b2c\u4e8c\u6b65\uff1a\u5728A=a1\u7684\u5c40\u90e8\u8303\u56f4\u5185\uff0c\u5b9a\u4f4db1\n            if b == b1 {\n                for c in sorted_C_within_a1_b1 {\n                    \/\/ \u7b2c\u4e09\u6b65\uff1a\u5728A=a1, B=b1\u7684\u5c40\u90e8\u8303\u56f4\u5185\uff0c\u5b9a\u4f4dc1\n                    if c == c1 {\n                        \/\/ \u627e\u5230\u4e86\uff01\u83b7\u53d6\u4e3b\u952e\uff0c\u51c6\u5907\u56de\u8868\n                    }\n                }\n            }\n        }\n    }\n}<\/pre>\n\n\n\n<p>\u7406\u89e3\u4e86\u8fd9\u4e2a\u6a21\u578b\uff0c\u6700\u5de6\u5339\u914d\u539f\u5219\u7684\u5404\u79cd\u60c5\u51b5\u5c31\u8fce\u5203\u800c\u89e3\u4e86\u3002<\/p>\n\n\n\n<ul>\n<li>\u5982\u679c\u67e5\u8be2\u6761\u4ef6\u662f <code>WHERE A = a1 AND B = b1<\/code>\uff0c\u90a3\u4e48\u53ef\u4ee5\u63a8\u65ad\u51fa\u6765\uff0c\u6570\u636e\u5e93\u53ea\u4f1a\u5e94\u7528\u5916\u5c42\u7684\u4e24\u91cd\u5faa\u73af\uff0c\u4e0d\u4f1a\u5bf9C\u8fdb\u884c\u8fc7\u6ee4\u3002<\/li>\n<\/ul>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ \u4f2a\u4ee3\u7801\u6f14\u793a WHERE A=a1 AND B=b1 \u7684\u67e5\u627e\u8fc7\u7a0b\nfor a in A {\n    if a == a1 {\n        for b in B {\n            if b == b1 {\n                \/\/ \u8fd9\u5c31\u662f\u4f60\u8981\u7684\u7ed3\u679c\uff0c\u83b7\u53d6\u4e3b\u952e\u53bb\u78c1\u76d8\u8bfb\u53d6\n            }\n        }\n    }\n}<\/pre>\n\n\n\n<ul>\n<li>\u5982\u679c\u67e5\u8be2\u6761\u4ef6\u662f <code>WHERE A = a1 OR B = b1<\/code>\uff0c\u90a3\u4e48\u8fd9\u4e2a\u67e5\u8be2\u901a\u5e38\u4e0d\u4f1a\u4f7f\u7528\u8fd9\u4e2a\u7ec4\u5408\u7d22\u5f15\uff0c\u56e0\u4e3a\u5b83\u65e0\u6cd5\u540c\u65f6\u6ee1\u8db3A\u548cB\u7684\u6709\u5e8f\u6027\u8fdb\u884c\u67e5\u627e\u3002<\/li>\n<\/ul>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ \u4f2a\u4ee3\u7801\u6f14\u793a WHERE A=a1 OR B=b1 \u7684\u67e5\u627e\u8fc7\u7a0b\n\/\/ \u5206\u522b\u67e5\u627e\u6ee1\u8db3\u6761\u4ef6\u7684a\u548cb\nas := find_all(A, a1)\nbs := find_all(B, b1)\n\/\/ \u5408\u5e76\u7ed3\u679c\u96c6\nresult := union(as, bs)<\/pre>\n\n\n\n<ul>\n<li>\u5982\u679c\u67e5\u8be2\u6761\u4ef6\u662f <code>WHERE A=a1 AND B &gt; b1 AND C=c1<\/code>\uff0c\u90a3\u4e48\u8fd9\u4e2a\u67e5\u8be2\u53ea\u4f1a\u4f7f\u7528\u7d22\u5f15\u7684A\u548cB\u4e24\u5217\u3002\u56e0\u4e3aB\u662f\u4e00\u4e2a\u8303\u56f4\u67e5\u8be2\uff0c\u4ece\u7b2c\u4e00\u4e2a\u6ee1\u8db3 <code>B &gt; b1<\/code> \u7684\u8bb0\u5f55\u5f00\u59cb\uff0c\u540e\u7eed\u7684C\u5217\u5c31\u65e0\u6cd5\u4fdd\u8bc1\u6709\u5e8f\u4e86\uff0c\u6240\u4ee5C\u5217\u4e0a\u7684\u7d22\u5f15\u5931\u6548\u3002<\/li>\n<\/ul>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ \u4f2a\u4ee3\u7801\u6f14\u793a WHERE A=a1 AND B > b1 AND C=c1 \u7684\u67e5\u627e\u8fc7\u7a0b\nfor a in A {\n    if a == a1 {\n        for b in B {\n            if b > b1 {\n                \/\/ C\u662f\u65e0\u5e8f\u7684\uff0c\u6240\u4ee5\u7528\u4e0d\u4e86\u7d22\u5f15\u3002\n                \/\/ \u8fd9\u5c31\u662f\u4f60\u8981\u7684\u7ed3\u679c\uff0c\u83b7\u53d6\u4e3b\u952e\u53bb\u78c1\u76d8\u8bfb\u53d6\n            }\n        }\n    }\n}<\/pre>\n\n\n\n<ul>\n<li>\u5982\u679c\u67e5\u8be2\u6761\u4ef6\u662f <code>WHERE A != a1<\/code>\uff0c\u90a3\u4e48\u8fd9\u4e2a\u67e5\u8be2\u4e5f\u4e0d\u4f1a\u4f7f\u7528\u7d22\u5f15\uff0c\u56e0\u4e3a\u4e0d\u7b49\u4e8e\u64cd\u4f5c\u7834\u574f\u4e86\u6709\u5e8f\u6027\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u4e00\u4e2a\u7b80\u5316\u7684\u5224\u65ad\u53e3\u8bc0\u662f\uff1a\u201c<strong>\u5e26\u5934\u5927\u54e5\u4e0d\u80fd\u4e22\uff0c\u4e2d\u95f4\u5144\u5f1f\u4e0d\u80fd\u65ad\uff0c\u8303\u56f4\u67e5\u8be2\u662f\u7ec8\u70b9<\/strong>\u201d\u3002\u67e5\u8be2\u6761\u4ef6\u5fc5\u987b\u4ece\u7d22\u5f15\u7684\u6700\u5de6\u5217\u5f00\u59cb\uff0c\u5e76\u4e14\u4e2d\u95f4\u4e0d\u80fd\u8df3\u8fc7\u67d0\u4e00\u5217\uff0c\u4e00\u65e6\u9047\u5230\u8303\u56f4\u67e5\u8be2\uff08<code>><\/code>\u3001<code>&lt;<\/code>\u3001<code>between<\/code>\u3001<code>like<\/code>\uff09\uff0c\u540e\u7eed\u7684\u5217\u7d22\u5f15\u4e5f\u5c06\u5931\u6548\u3002<\/p>\n\n\n\n<p>\u5f53\u7136\uff0c\u8fd9\u53ea\u662f\u4e00\u4e2a\u901a\u7528\u6cd5\u5219\uff0c\u73b0\u4ee3\u6570\u636e\u5e93\u4f18\u5316\u5668\u8d8a\u6765\u8d8a\u667a\u80fd\uff0c\u6709\u65f6\u4e5f\u4f1a\u505a\u51fa\u4e00\u4e9b\u4f18\u5316\u3002\u4f46\u5728\u5b9e\u8df5\u4e2d\uff0c\u6700\u6743\u5a01\u7684\u5224\u65ad\u65b9\u5f0f\u6c38\u8fdc\u662f <code>EXPLAIN<\/code> \u547d\u4ee4\u7684\u8f93\u51fa\u7ed3\u679c\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p><strong>\u5bf9\u7ec4\u5408\u7d22\u5f15\u00a0<code>&lt;A, B, C><\/code>\u8be6\u7ec6\u89e3\u91ca<\/strong><\/p>\n\n\n\n<p>\u8981\u7406\u89e3\u7ec4\u5408\u7d22\u5f15\u7684 \u201c\u6700\u5de6\u5339\u914d\u539f\u5219\u201d \u548c\u8303\u56f4\u67e5\u8be2\u5bf9\u7d22\u5f15\u7684\u5f71\u54cd\uff0c\u6211\u4eec\u53ef\u4ee5\u4ece\u7ec4\u5408\u7d22\u5f15\u7684<strong>\u7269\u7406\u5b58\u50a8\u7ed3\u6784<\/strong>\u548c<strong>\u67e5\u8be2\u5339\u914d\u903b\u8f91<\/strong>\u4e24\u65b9\u9762\u8be6\u7ec6\u89e3\u91ca\uff1a<\/p>\n\n\n\n<p>\u7ec4\u5408\u7d22\u5f15\u7684\u6392\u5e8f\u89c4\u5219\uff1a\u672c\u8d28\u662f \u201c\u524d\u7f00\u6709\u5e8f\u201d<\/p>\n\n\n\n<p>\u7ec4\u5408\u7d22\u5f15&nbsp;<code>&lt;A, B, C&gt;<\/code>&nbsp;\u5728\u78c1\u76d8\u4e0a\u7684\u5b58\u50a8\u662f<strong>\u5148\u6309 A \u6392\u5e8f\uff0cA \u76f8\u540c\u518d\u6309 B \u6392\u5e8f\uff0cB \u76f8\u540c\u518d\u6309 C \u6392\u5e8f<\/strong>\uff0c\u7c7b\u4f3c\u5b57\u5178\u7684\u6392\u5e8f\u903b\u8f91\uff08\u5148\u6309\u9996\u5b57\u6bcd\uff0c\u518d\u6309\u7b2c\u4e8c\u4e2a\u5b57\u6bcd&#8230;\uff09\u3002<\/p>\n\n\n\n<p>\u4f8b\u5982\uff0c\u7d22\u5f15\u6761\u76ee\u53ef\u80fd\u957f\u8fd9\u6837\uff08\u6309\u987a\u5e8f\u6392\u5217\uff09\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">(A=1, B=2, C=3)\n(A=1, B=2, C=5)\n(A=1, B=3, C=2)\n(A=1, B=4, C=6)\n(A=2, B=1, C=4)\n(A=2, B=2, C=1)\n...<\/pre>\n\n\n\n<ul>\n<li>\u6240\u6709\u8bb0\u5f55\u5148\u6309 A \u5206\u7ec4\u6392\u5e8f\uff08A=1 \u7684\u6240\u6709\u8bb0\u5f55\u6392\u5728 A=2 \u4e4b\u524d\uff09\u3002<\/li>\n\n\n\n<li>\u540c\u4e00 A \u503c\u5185\uff0c\u6309 B \u6392\u5e8f\uff08A=1 \u4e2d\uff0cB=2 \u7684\u8bb0\u5f55\u6392\u5728 B=3 \u4e4b\u524d\uff09\u3002<\/li>\n\n\n\n<li>\u540c\u4e00 A \u548c B \u503c\u5185\uff0c\u6309 C \u6392\u5e8f\uff08A=1\u3001B=2 \u4e2d\uff0cC=3 \u6392\u5728 C=5 \u4e4b\u524d\uff09\u3002<\/li>\n<\/ul>\n\n\n\n<p><strong>\u6700\u5de6\u5339\u914d\u539f\u5219\uff1a\u4ece\u5de6\u5230\u53f3\u4f9d\u6b21\u5339\u914d\uff0c\u4e2d\u65ad\u540e\u5931\u6548<\/strong><\/p>\n\n\n\n<p>\u67e5\u8be2\u65f6\uff0c\u6570\u636e\u5e93\u4f1a<strong>\u4ece\u7d22\u5f15\u7684\u6700\u5de6\u5217\uff08A\uff09\u5f00\u59cb\u5339\u914d<\/strong>\uff0c\u53ea\u6709\u5f53\u5de6\u8fb9\u7684\u5217\u5339\u914d\u6210\u529f\u540e\uff0c\u624d\u4f1a\u4f7f\u7528\u53f3\u8fb9\u7684\u5217\u3002\u5982\u679c\u4e2d\u95f4\u67d0\u4e00\u5217\u65e0\u6cd5\u5339\u914d\uff08\u6216\u4f7f\u7528\u8303\u56f4\u67e5\u8be2\u5bfc\u81f4\u6709\u5e8f\u6027\u7834\u574f\uff09\uff0c\u5219\u5176\u53f3\u4fa7\u7684\u6240\u6709\u5217\u90fd\u65e0\u6cd5\u518d\u4f7f\u7528\u7d22\u5f15\u3002<\/p>\n\n\n\n<p>\u4ee5\u67e5\u8be2\u6761\u4ef6&nbsp;<code>WHERE A=a1 AND B &gt; b1 AND C=c1<\/code>&nbsp;\u4e3a\u4f8b\uff1a<\/p>\n\n\n\n<p><strong>1. A \u5217\uff1a\u5b8c\u5168\u5339\u914d\uff0c\u7d22\u5f15\u6709\u6548<\/strong><\/p>\n\n\n\n<ul>\n<li>\u6761\u4ef6\u00a0<code>A=a1<\/code>\u00a0\u662f \u201c\u7b49\u4e8e\u201d \u67e5\u8be2\uff0c\u6570\u636e\u5e93\u4f1a\u5148\u5728\u7d22\u5f15\u4e2d\u5b9a\u4f4d\u5230\u6240\u6709\u00a0<code>A=a1<\/code>\u00a0\u7684\u8bb0\u5f55\uff08\u8fd9\u4e9b\u8bb0\u5f55\u5728\u7269\u7406\u4e0a\u662f\u8fde\u7eed\u5b58\u50a8\u7684\uff0c\u56e0\u4e3a\u7d22\u5f15\u6309 A \u6392\u5e8f\uff09\u3002<\/li>\n\n\n\n<li>\u6b64\u65f6\uff0cA \u5217\u7684\u7d22\u5f15\u5b8c\u5168\u751f\u6548\uff0c\u7f29\u5c0f\u4e86\u67e5\u8be2\u8303\u56f4\uff08\u53ea\u5904\u7406 A=a1 \u7684\u5206\u7ec4\uff09\u3002<\/li>\n<\/ul>\n\n\n\n<p><strong>2. B \u5217\uff1a\u8303\u56f4\u67e5\u8be2\uff0c\u7d22\u5f15\u90e8\u5206\u6709\u6548<\/strong><\/p>\n\n\n\n<ul>\n<li>\u6761\u4ef6\u00a0<code>B > b1<\/code>\u00a0\u662f \u201c\u8303\u56f4\u201d \u67e5\u8be2\uff08\u5927\u4e8e\uff09\u3002\u5728 A=a1 \u7684\u5206\u7ec4\u5185\uff0c\u8bb0\u5f55\u6309 B \u6392\u5e8f\uff0c\u56e0\u6b64\u6570\u636e\u5e93\u53ef\u4ee5\u5feb\u901f\u627e\u5230\u7b2c\u4e00\u4e2a\u00a0<code>B > b1<\/code>\u00a0\u7684\u4f4d\u7f6e\uff0c\u7136\u540e\u5411\u53f3\u626b\u63cf\u6240\u6709\u7b26\u5408\u6761\u4ef6\u7684\u8bb0\u5f55\u3002<\/li>\n\n\n\n<li>\u6b64\u65f6\uff0cB \u5217\u7684\u7d22\u5f15\u4ecd\u6709\u6548\uff08\u5229\u7528\u4e86 B \u7684\u6709\u5e8f\u6027\u5b9a\u4f4d\u8303\u56f4\u8d77\u70b9\uff09\uff0c\u4f46<strong>\u8303\u56f4\u67e5\u8be2\u4f1a\u7834\u574f\u540e\u7eed\u5217\u7684\u6709\u5e8f\u6027<\/strong>\u3002<\/li>\n<\/ul>\n\n\n\n<p><strong>3. C \u5217\uff1a\u7d22\u5f15\u5931\u6548<\/strong><\/p>\n\n\n\n<ul>\n<li>\u6761\u4ef6\u00a0<code>C=c1<\/code>\u00a0\u662f \u201c\u7b49\u4e8e\u201d \u67e5\u8be2\uff0c\u4f46\u6b64\u65f6 C \u5217\u7684\u7d22\u5f15\u65e0\u6cd5\u751f\u6548\uff0c\u539f\u56e0\u662f\uff1a\n<ul>\n<li>\u5728\u00a0<code>B > b1<\/code>\u00a0\u7684\u8303\u56f4\u5185\uff0cB \u7684\u503c\u662f\u65e0\u5e8f\u589e\u957f\u7684\uff08\u4f8b\u5982 B=3\u30014\u30015&#8230;\uff09\uff0c\u800c C \u7684\u6392\u5e8f\u4f9d\u8d56\u4e8e B \u7684\u503c\uff08\u53ea\u6709 B \u76f8\u540c\u65f6 C \u624d\u6709\u5e8f\uff09\u3002<\/li>\n\n\n\n<li>\u5f53 B \u7684\u503c\u53d8\u5316\u65f6\uff0cC \u7684\u503c\u53ef\u80fd\u662f\u4e71\u5e8f\u7684\uff08\u6bd4\u5982 B=3 \u65f6 C=2\uff0cB=4 \u65f6 C=6\uff0cB=5 \u65f6 C=1\uff09\uff0c\u56e0\u6b64\u65e0\u6cd5\u901a\u8fc7 C \u5217\u7684\u7d22\u5f15\u5feb\u901f\u5b9a\u4f4d\u00a0<code>C=c1<\/code>\u00a0\u7684\u8bb0\u5f55\u3002<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>\u6570\u636e\u5e93\u53ea\u80fd\u5728\u00a0<code>A=a1 AND B > b1<\/code>\u00a0\u7684\u8303\u56f4\u5185\uff0c\u9010\u6761\u626b\u63cf\u8bb0\u5f55\u5e76\u5224\u65ad C \u662f\u5426\u7b49\u4e8e c1\uff08\u5168\u8868\u626b\u63cf\u7684\u5b50\u96c6\uff0c\u6548\u7387\u8f83\u4f4e\uff09\u3002<\/li>\n<\/ul>\n\n\n\n<p><strong>\u76f4\u89c2\u4e3e\u4f8b\uff1a\u4e3a\u4ec0\u4e48 C \u5217\u5931\u6548\uff1f<\/strong><\/p>\n\n\n\n<p>\u5047\u8bbe&nbsp;<code>a1=1<\/code>\uff0c<code>b1=2<\/code>\uff0c\u5373\u67e5\u8be2&nbsp;<code>WHERE A=1 AND B&gt;2 AND C=6<\/code>\uff1a<\/p>\n\n\n\n<p>\u5728\u4e4b\u524d\u7684\u7d22\u5f15\u793a\u4f8b\u4e2d\uff1a<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">(A=1, B=2, C=3)  \u2192 B\u4e0d\u6ee1\u8db3>2\uff0c\u6392\u9664\n(A=1, B=2, C=5)  \u2192 B\u4e0d\u6ee1\u8db3>2\uff0c\u6392\u9664\n(A=1, B=3, C=2)  \u2192 B\u6ee1\u8db3>2\uff0c\u4f46C\u22606\n(A=1, B=4, C=6)  \u2192 B\u6ee1\u8db3>2\uff0cC=6\uff08\u76ee\u6807\u8bb0\u5f55\uff09\n(A=2, B=1, C=4)  \u2192 A\u22601\uff0c\u6392\u9664\n...<\/pre>\n\n\n\n<ul>\n<li>A=1 \u7684\u5206\u7ec4\u4e2d\uff0cB>2 \u7684\u8303\u56f4\u662f\u00a0<code>(B=3, C=2)<\/code>\u00a0\u548c\u00a0<code>(B=4, C=6)<\/code>\u3002<\/li>\n\n\n\n<li>\u8fd9\u4e24\u6761\u8bb0\u5f55\u7684 C \u503c\u662f 2 \u548c 6\uff0c\u662f\u65e0\u5e8f\u7684\uff08\u56e0\u4e3a B \u4e0d\u540c\uff09\uff0c\u6240\u4ee5\u65e0\u6cd5\u901a\u8fc7 C \u7684\u7d22\u5f15\u76f4\u63a5\u627e\u5230 6\uff0c\u53ea\u80fd\u9010\u6761\u68c0\u67e5\u3002<\/li>\n<\/ul>\n\n\n\n<p><strong>\u6269\u5c55\uff1a\u54ea\u4e9b\u60c5\u51b5\u4f1a\u5bfc\u81f4\u540e\u7eed\u7d22\u5f15\u5931\u6548\uff1f<\/strong><\/p>\n\n\n\n<p>\u9664\u4e86&nbsp;<code>&gt;<\/code>\uff0c\u4ee5\u4e0b\u64cd\u4f5c\u4e5f\u4f1a\u7834\u574f\u7d22\u5f15\u7684\u6709\u5e8f\u6027\uff0c\u5bfc\u81f4\u53f3\u4fa7\u5217\u5931\u6548\uff1a<\/p>\n\n\n\n<ul>\n<li>\u8303\u56f4\u64cd\u4f5c\uff1a<code>B &lt; b1<\/code>\u3001<code>B >= b1<\/code>\u3001<code>B &lt;= b1<\/code>\u3001<code>B BETWEEN b1 AND b2<\/code><\/li>\n\n\n\n<li>\u4e0d\u7b49\u4e8e\u64cd\u4f5c\uff1a<code>B != b1<\/code>\u3001<code>B &lt;> b1<\/code><\/li>\n\n\n\n<li>\u6a21\u7cca\u67e5\u8be2\uff1a<code>B LIKE '%x'<\/code>\uff08\u901a\u914d\u7b26\u5f00\u5934\uff09<\/li>\n<\/ul>\n\n\n\n<p><strong>\u4f8b\u5916<\/strong>\uff1a<code>B = b1<\/code>\uff08\u7b49\u4e8e\uff09\u4e0d\u4f1a\u7834\u574f\u6709\u5e8f\u6027\uff0c\u6b64\u65f6 C \u5217\u7684\u7d22\u5f15\u4ecd\u53ef\u751f\u6548\uff08\u56e0\u4e3a B \u76f8\u540c\u7684\u8bb0\u5f55\u4e2d C \u662f\u6709\u5e8f\u7684\uff09\u3002<\/p>\n\n\n\n<p><strong>\u603b\u7ed3<\/strong>\uff1a\u7ec4\u5408\u7d22\u5f15\u00a0<code>&lt;A, B, C><\/code>\u00a0\u7684\u6700\u5de6\u5339\u914d\u539f\u5219\u6838\u5fc3\u662f\uff1a<\/p>\n\n\n\n<ol>\n<li>\u7d22\u5f15\u6309\u4ece\u5de6\u5230\u53f3\u7684\u987a\u5e8f\u6392\u5e8f\uff0c\u5fc5\u987b\u4ece\u6700\u5de6\u5217\u5f00\u59cb\u5339\u914d\u3002<\/li>\n\n\n\n<li>\u4e00\u65e6\u67d0\u4e00\u5217\u4f7f\u7528\u4e86\u8303\u56f4\u67e5\u8be2\uff08\u6216\u7834\u574f\u6709\u5e8f\u6027\u7684\u64cd\u4f5c\uff09\uff0c\u5176\u53f3\u4fa7\u7684\u6240\u6709\u5217\u7d22\u5f15\u90fd\u4f1a\u5931\u6548\u3002<\/li>\n\n\n\n<li>\u56e0\u6b64\uff0c<code>WHERE A=a1 AND B > b1 AND C=c1<\/code>\u00a0\u53ea\u80fd\u7528\u5230 A \u548c B \u5217\u7684\u7d22\u5f15\uff0cC \u5217\u65e0\u6cd5\u5229\u7528\u7d22\u5f15\u3002<\/li>\n<\/ol>\n\n\n\n<p>\u5728\u8bbe\u8ba1\u7ec4\u5408\u7d22\u5f15\u65f6\uff0c\u5e94\u5c06<strong>\u9891\u7e41\u7cbe\u786e\u5339\u914d\u7684\u5217\u653e\u5728\u5de6\u8fb9<\/strong>\uff0c<strong>\u8303\u56f4\u67e5\u8be2\u7684\u5217\u653e\u5728\u53f3\u8fb9<\/strong>\uff0c\u4ee5\u6700\u5927\u5316\u7d22\u5f15\u5229\u7528\u7387\u3002<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p><strong>1.6 \u7d22\u5f15\u7684\u4ee3\u4ef7<\/strong><\/p>\n\n\n\n<p>\u5929\u4e0b\u6ca1\u6709\u514d\u8d39\u7684\u5348\u9910\uff0c\u7d22\u5f15\u5728\u5e26\u6765\u67e5\u8be2\u52a0\u901f\u7684\u540c\u65f6\uff0c\u4e5f\u5fc5\u7136\u4f1a\u4ea7\u751f\u4e00\u4e9b\u5f00\u9500\u548c\u526f\u4f5c\u7528\uff1a<\/p>\n\n\n\n<ol>\n<li><strong>\u7a7a\u95f4\u6210\u672c<\/strong>\uff1a\u7d22\u5f15\u672c\u8eab\u662f\u6570\u636e\u7ed3\u6784\uff0c\u9700\u8981\u5b58\u50a8\u5728\u78c1\u76d8\u4e0a\uff0c\u4f1a\u5360\u7528\u989d\u5916\u7684\u7269\u7406\u7a7a\u95f4\u3002<\/li>\n\n\n\n<li><strong>\u65f6\u95f4\u6210\u672c<\/strong>\uff1a\u5f53\u5bf9\u8868\u4e2d\u7684\u6570\u636e\u8fdb\u884c\u589e\u3001\u5220\u3001\u6539\u64cd\u4f5c\u65f6\uff0c\u4e0d\u4ec5\u8981\u4fee\u6539\u6570\u636e\u672c\u8eab\uff0c\u8fd8\u5fc5\u987b\u540c\u6b65\u7ef4\u62a4\u76f8\u5173\u7684B+\u6811\u7d22\u5f15\uff0c\u4ee5\u4fdd\u8bc1\u7d22\u5f15\u7684\u6709\u5e8f\u6027\u3002\u8fd9\u4e2a\u8fc7\u7a0b\u4f1a\u5f15\u5165\u989d\u5916\u7684\u6027\u80fd\u5f00\u9500\uff0c\u964d\u4f4e\u5199\u5165\u6027\u80fd\u3002<\/li>\n\n\n\n<li><strong>\u5185\u5b58\u6210\u672c<\/strong>\uff1a\u8fd0\u884c\u65f6\uff0c\u7d22\u5f15\u4f1a\u88ab\u52a0\u8f7d\u5230\u5185\u5b58\u4e2d\uff0c\u6d88\u8017\u5b9d\u8d35\u7684\u5185\u5b58\u8d44\u6e90\u3002<\/li>\n<\/ol>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"521\" src=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-255-1024x521.png\" alt=\"\" class=\"wp-image-18976\" style=\"width:454px;height:auto\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-255-1024x521.png 1024w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-255-300x153.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-255-768x391.png 768w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-255-830x422.png 830w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-255-230x117.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-255-350x178.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-255-480x244.png 480w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-255.png 1266w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure><\/div>\n\n\n<p><a href=\"https:\/\/golangstar.cn\/backend_series\/advanced_interview\/database_index.html#_1-6-\u7d22\u5f15\u7684\u4ee3\u4ef7\"><\/a>\u8bb0\u4f4f\u8fd9\u4e9b\u4ee3\u4ef7\u975e\u5e38\u91cd\u8981\u3002\u9762\u8bd5\u5b98\u5f88\u53ef\u80fd\u4f1a\u53cd\u5176\u9053\u800c\u884c\u4e4b\uff0c\u5728\u4f60\u6ed4\u6ed4\u4e0d\u7edd\u5730\u8bb2\u8ff0\u7d22\u5f15\u7684\u4f18\u70b9\u540e\uff0c\u7a81\u7136\u53d1\u95ee\uff1a\u201c\u7d22\u5f15\u6709\u4ec0\u4e48\u7f3a\u70b9\uff1f\u201d\u6216\u201c\u4ec0\u4e48\u60c5\u51b5\u4e0b\u4e0d\u5e94\u8be5\u4f7f\u7528\u7d22\u5f15\uff1f\u201d\u3002<a href=\"https:\/\/golangstar.cn\/backend_series\/advanced_interview\/database_index.html#_1-6-\u7d22\u5f15\u7684\u4ee3\u4ef7\"><\/a><\/p>\n\n\n\n<p>\u3000<\/p>\n\n\n\n<p><strong>2. \u51b3\u80dc\u9762\u8bd5\uff1a\u7d22\u5f15\u77e5\u8bc6\u7684\u5b9e\u6218\u7b56\u7565<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>\u5728\u9762\u8bd5\u4e2d\uff0c\u6211\u4eec\u4e0d\u4ec5\u8981\u5c55\u793a\u81ea\u5df1\u201c\u77e5\u9053\u4ec0\u4e48\u201d\uff0c\u66f4\u8981\u5c55\u793a\u201c\u5982\u4f55\u601d\u8003\u201d\u3002<\/p>\n\n\n\n<p>\u5f53\u4f60\u51c6\u5907\u9762\u8bd5\u65f6\uff0c\u6700\u597d\u80fd\u7ed3\u5408\u81ea\u5df1\u53c2\u4e0e\u8fc7\u7684\u9879\u76ee\uff0c\u804a\u804a\u5176\u4e2d\u7684\u7d22\u5f15\u8bbe\u8ba1\uff0c\u4ee5\u53ca\u662f\u5426\u9047\u5230\u8fc7\u56e0\u7d22\u5f15\u4e0d\u5f53\u800c\u5f15\u53d1\u7684\u7ebf\u4e0a\u95ee\u9898\u3002\u5982\u679c\u4f60\u60f3\u5851\u9020\u81ea\u5df1\u201c\u7cbe\u901a\u9ad8\u6027\u80fd\u67b6\u6784\u201d\u7684\u5f62\u8c61\uff0c\u90a3\u4e48\u5728\u9879\u76ee\u4ecb\u7ecd\u73af\u8282\u4e3b\u52a8\u63d0\u53caSQL\u4f18\u5316\u548c\u7d22\u5f15\u8bbe\u8ba1\uff0c\u65e0\u7591\u662f\u4e00\u4e2a\u5f88\u597d\u7684\u5207\u5165\u70b9\u3002<\/p>\n\n\n\n<p>\u9762\u8bd5\u5b98\u53ef\u80fd\u4f1a\u76f4\u63a5\u629b\u51fa\u4e00\u4e2a\u5177\u4f53\u7684SQL\uff0c\u8ba9\u4f60\u5224\u65ad\u662f\u5426\u4f1a\u4f7f\u7528\u7d22\u5f15\u3002\u9047\u5230\u8fd9\u7c7b\u95ee\u9898\uff0c\u5207\u8bb0\u4e0d\u8981\u6025\u4e8e\u56de\u7b54\u3002\u9996\u5148\u8981\u5f3a\u8c03\uff0c\u4f60\u7684\u5224\u65ad\u662f\u57fa\u4e8e\u201c\u4e00\u822c\u60c5\u51b5\u201d\u4e0b\u7684\u3002\u7136\u540e\u53ef\u4ee5\u8865\u5145\u4e00\u53e5\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">\u201c\u6211\u521a\u624d\u7684\u5206\u6790\u662f\u57fa\u4e8e\u901a\u7528\u89c4\u5219\u7684\u3002\u4f46\u5728\u5b9e\u9645\u573a\u666f\u4e2d\uff0c\u6570\u636e\u5e93\u662f\u5426\u4f7f\u7528\u7d22\u5f15\uff0c\u8fd8\u4f1a\u53d7\u5230\u8868\u7684\u6570\u636e\u91cf\u3001\u6570\u636e\u7684\u5206\u5e03\u60c5\u51b5\u3001\u4ee5\u53ca\u662f\u5426\u5b58\u5728\u5176\u4ed6\u53ef\u7528\u7d22\u5f15\u7b49\u591a\u91cd\u56e0\u7d20\u7684\u5f71\u54cd\u3002MySQL\u7684\u4f18\u5316\u5668\u4f1a\u7efc\u5408\u8bc4\u4f30\u5404\u79cd\u67e5\u8be2\u8def\u5f84\u7684\u6210\u672c\uff0c\u9009\u62e9\u5b83\u8ba4\u4e3a\u6700\u4f18\u7684\u6267\u884c\u8ba1\u5212\u3002\u6700\u51c6\u786e\u7684\u65b9\u5f0f\u8fd8\u662f\u901a\u8fc7EXPLAIN\u6765\u5206\u6790\u3002\u201d<\/pre>\n\n\n\n<p>\u8fd9\u6837\u4e00\u6bb5\u201c\u514d\u8d23\u58f0\u660e\u201d\uff0c\u65e2\u80fd\u4f53\u73b0\u4f60\u601d\u7ef4\u7684\u4e25\u8c28\u6027\uff0c\u53c8\u80fd\u5de7\u5999\u5730\u5c06\u8bdd\u9898\u5f15\u5411\u66f4\u6df1\u5c42\u6b21\u7684\u8ba8\u8bba\uff0c\u6bd4\u5982\u201c\u4e3a\u4ec0\u4e48\u6570\u636e\u5e93\u6709\u65f6\u4f1a\u653e\u5f03\u4f7f\u7528\u7d22\u5f15\u201d\u3002<\/p>\n\n\n\n<p>\u5982\u679c\u9762\u8bd5\u5b98\u95ee\u53ca\u4ee5\u4e0b\u95ee\u9898\uff0c\u4f60\u90fd\u53ef\u4ee5\u987a\u52bf\u5c06\u8bdd\u9898\u5f15\u5bfc\u5230\u7d22\u5f15\u4e0a\uff1a<\/p>\n\n\n\n<ul>\n<li>\u4f60\u505a\u8fc7\u54ea\u4e9b\u6027\u80fd\u4f18\u5316\u5de5\u4f5c\uff1f<\/li>\n\n\n\n<li>\u4f60\u5bf9B\u6811\u548cB+\u6811\u4e86\u89e3\u591a\u5c11\uff1f<\/li>\n\n\n\n<li>\u805a\u7c07\u7d22\u5f15\u548c\u8986\u76d6\u7d22\u5f15\u6709\u4ec0\u4e48\u533a\u522b\uff1f<\/li>\n\n\n\n<li>\u6570\u636e\u5e93\u67e5\u8be2\u4e00\u5b9a\u4f1a\u8d70\u7d22\u5f15\u5417\uff1f<\/li>\n\n\n\n<li>\u662f\u4e0d\u662f\u52a0\u4e86\u7d22\u5f15\uff0c\u67e5\u8be2\u5c31\u4e00\u5b9a\u4f1a\u53d8\u5feb\uff1f<\/li>\n<\/ul>\n\n\n\n<p><strong>2.1 \u7d22\u5f15\u7684\u6838\u5fc3\u8bdd\u672f<a href=\"https:\/\/golangstar.cn\/backend_series\/advanced_interview\/database_index.html#_2-1-\u7d22\u5f15\u7684\u6838\u5fc3\u8bdd\u672f\"><\/a><\/strong><\/p>\n\n\n\n<p>\u5982\u679c\u9762\u8bd5\u5b98\u53ea\u662f\u7b3c\u7edf\u5730\u95ee\u4f60\u5bf9\u7d22\u5f15\u7684\u7406\u89e3\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528\u4e0b\u9762\u8fd9\u6bb5\u8bdd\u672f\u4f5c\u4e3a\u5f00\u573a\uff0c\u5b83\u7cfb\u7edf\u6027\u5730\u4e32\u8054\u4e86B+\u6811\u3001\u7d22\u5f15\u5206\u7c7b\u548c\u6700\u5de6\u5339\u914d\u539f\u5219\uff0c\u5e76\u57cb\u4e0b\u4e86\u51e0\u4e2a\u53ef\u4ee5\u6df1\u5165\u63a2\u8ba8\u7684\u5f15\u5b50\u3002<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">\u201c\u5728\u6211\u770b\u6765\uff0c\u7406\u89e3MySQL\u7d22\u5f15\u53ef\u4ee5\u4ece\u4e09\u4e2a\u5c42\u9762\u5165\u624b\u3002\u9996\u5148\uff0c\u4ece\u5e95\u5c42\u6570\u636e\u7ed3\u6784\u6765\u770b\uff0cInnoDB\u4e3b\u8981\u91c7\u7528B+\u6811\u3002\u76f8\u6bd4\u4e8e\u5176\u4ed6\u6570\u636e\u7ed3\u6784\uff0cB+\u6811\u7684\u6811\u9ad8\u66f4\u4f4e\u3001I\/O\u6548\u7387\u66f4\u9ad8\uff0c\u5e76\u4e14\u901a\u8fc7\u53f6\u5b50\u8282\u70b9\u7684\u94fe\u8868\u8bbe\u8ba1\uff0c\u5929\u7136\u652f\u6301\u9ad8\u6548\u7684\u8303\u56f4\u67e5\u8be2\u3002\u540c\u65f6\uff0c\u5b83\u975e\u53f6\u5b50\u8282\u70b9\u4e0d\u5b58\u6570\u636e\u7684\u7279\u6027\uff0c\u4e5f\u8ba9\u5b83\u66f4\u8282\u7701\u5185\u5b58\u3002<br>\u5176\u6b21\uff0c\u4ece\u5e94\u7528\u89d2\u5ea6\u770b\uff0c\u7d22\u5f15\u53ef\u4ee5\u5206\u4e3a\u805a\u7c07\u7d22\u5f15\u548c\u975e\u805a\u7c07\u7d22\u5f15\uff0c\u8fd9\u51b3\u5b9a\u4e86\u6570\u636e\u548c\u7d22\u5f15\u7684\u5b58\u50a8\u65b9\u5f0f\uff0c\u5e76\u5f15\u51fa\u4e86\u2018\u56de\u8868\u2019\u548c\u2018\u8986\u76d6\u7d22\u5f15\u2019\u7b49\u4f18\u5316\u70b9\u3002<br>\u6700\u540e\uff0c\u4ece\u4f7f\u7528\u89c4\u5219\u4e0a\u8bb2\uff0c\u7ec4\u5408\u7d22\u5f15\u9075\u5faa\u6700\u5de6\u5339\u914d\u539f\u5219\u3002\u4e0d\u8fc7\uff0c\u6700\u7ec8\u6570\u636e\u5e93\u4f1a\u4e0d\u4f1a\u7528\u7d22\u5f15\uff0c\u8fd8\u662f\u4e00\u4e2a\u52a8\u6001\u51b3\u7b56\u7684\u8fc7\u7a0b\uff0c\u4e0e\u67e5\u8be2\u8bed\u53e5\u672c\u8eab\u3001\u6570\u636e\u5206\u5e03\u90fd\u6709\u5173\u7cfb\u3002\u5728\u5b9e\u8df5\u4e2d\uff0c\u6211\u4eec\u8fd8\u662f\u8981\u4ee5EXPLAIN\u7684\u5206\u6790\u7ed3\u679c\u4e3a\u51c6\u3002\u201d<\/pre>\n\n\n\n<p>\u8fd9\u6bb5\u8bdd\u672f\u4e2d\uff0c\u6709\u51e0\u4e2a\u70b9\u5f88\u5bb9\u6613\u6fc0\u53d1\u9762\u8bd5\u5b98\u7684\u8ffd\u95ee\u5174\u8da3\uff1a<\/p>\n\n\n\n<ol>\n<li>\u4e3a\u4ec0\u4e48MySQL\u9009\u62e9\u4e86B+\u6811\uff0c\u800c\u4e0d\u662fB\u6811\u3001\u7ea2\u9ed1\u6811\u6216\u8df3\u8868\uff1f<\/li>\n\n\n\n<li>\u4ec0\u4e48\u662f\u56de\u8868\uff1f\u5982\u4f55\u901a\u8fc7\u8986\u76d6\u7d22\u5f15\u8fdb\u884c\u4f18\u5316\uff1f\uff08\u53ef\u5f15\u7533\u5230SQL\u4f18\u5316\uff09<\/li>\n\n\n\n<li>\u5728\u54ea\u4e9b\u60c5\u51b5\u4e0b\uff0c\u6570\u636e\u5e93\u660e\u660e\u6709\u7d22\u5f15\u5374\u4e0d\u4f7f\u7528\uff1f<\/li>\n<\/ol>\n\n\n\n<p><strong>2.2 \u9762\u8bd5\u52a0\u5206\u9879\uff1a\u5c55\u73b0\u4f60\u7684\u6280\u672f\u6df1\u5ea6<a href=\"https:\/\/golangstar.cn\/backend_series\/advanced_interview\/database_index.html#_2-2-\u9762\u8bd5\u52a0\u5206\u9879-\u5c55\u73b0\u4f60\u7684\u6280\u672f\u6df1\u5ea6\"><\/a><\/strong><\/p>\n\n\n\n<p>\u63a5\u4e0b\u6765\uff0c\u6211\u4eec\u6765\u9010\u4e00\u653b\u514b\u4e0a\u9762\u8fd9\u4e9b\u80fd\u591f\u8ba9\u4f60\u5728\u9762\u8bd5\u4e2d\u8131\u9896\u800c\u51fa\u7684\u4eae\u70b9\u95ee\u9898\u3002<\/p>\n\n\n\n<p><strong>2.2.1 \u4eae\u70b9\u4e00\uff1a\u4e3a\u4ec0\u4e48\u662fB+\u6811\uff1f<\/strong><\/p>\n\n\n\n<p>\u8981\u56de\u7b54\u597d\u8fd9\u4e2a\u95ee\u9898\uff0c\u4f60\u9700\u8981\u5c06B+\u6811\u653e\u5728\u4e00\u4e2a\u66f4\u5e7f\u9614\u7684\u821e\u53f0\u4e0a\uff0c\u4e0e\u5176\u5b83\u51e0\u79cd\u5907\u9009\u7684\u6570\u636e\u7ed3\u6784\u8fdb\u884c\u6a2a\u5411\u5bf9\u6bd4\uff0c\u4ece\u800c\u51f8\u663e\u5176\u4f18\u52bf\u3002<\/p>\n\n\n\n<ul>\n<li><strong>\u5bf9\u6bd4\u5e73\u8861\u4e8c\u53c9\u6811\/\u7ea2\u9ed1\u6811<\/strong>\uff1a\u8fd9\u4e9b\u90fd\u662f\u7ecf\u5178\u7684\u4e8c\u8def\u6216\u51c6\u4e8c\u8def\u641c\u7d22\u6811\u3002\u5728\u6570\u636e\u91cf\u5de8\u5927\u65f6\uff0c\u5b83\u4eec\u7684\u6811\u9ad8\u4f1a\u975e\u5e38\u53ef\u89c2\u3002\u6811\u7684\u9ad8\u5ea6\u51b3\u5b9a\u4e86\u78c1\u76d8I\/O\u7684\u6b21\u6570\uff0c\u8fc7\u9ad8\u7684\u6811\u610f\u5473\u7740\u6027\u80fd\u6025\u5267\u4e0b\u964d\u3002\u800c\u4e14\uff0c\u4e3a\u4e86\u7ef4\u6301\u5e73\u8861\uff0c\u5b83\u4eec\u7684\u63d2\u5165\u548c\u5220\u9664\u64cd\u4f5c\u53ef\u80fd\u4f1a\u5f15\u53d1\u9891\u7e41\u7684\u6811\u65cb\u8f6c\uff0c\u5f00\u9500\u8f83\u5927\u3002<\/li>\n<\/ul>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"397\" src=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-256-1024x397.png\" alt=\"\" class=\"wp-image-18977\" style=\"width:482px;height:auto\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-256-1024x397.png 1024w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-256-300x116.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-256-768x297.png 768w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-256-830x321.png 830w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-256-230x89.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-256-350x136.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-256-480x186.png 480w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-256.png 1296w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure><\/div>\n\n\n<ul>\n<li><strong>\u5bf9\u6bd4\u8df3\u8868 (Skip List)<\/strong>\uff1a\u8df3\u8868\u662f\u4e00\u79cd\u901a\u8fc7\u201c\u5347\u7ef4\u201d\u601d\u60f3\u5b9e\u73b0\u7684\u94fe\u8868\uff0c\u67e5\u8be2\u6027\u80fd\u5728\u671f\u671b\u4e0a\u53ef\u4ee5\u8fbe\u5230 <code>O(logN)<\/code>\u3002\u4f46\u5b83\u7684\u95ee\u9898\u5728\u4e8e\uff0c\u5e73\u8861\u6027\u4f9d\u8d56\u4e8e\u968f\u673a\u5316\uff0c\u5728\u6781\u7aef\u60c5\u51b5\u4e0b\u53ef\u80fd\u9000\u5316\u6210\u4e00\u4e2a\u666e\u901a\u94fe\u8868\uff0c\u5bfc\u81f4\u67e5\u8be2\u6027\u80fd\u6781\u4e0d\u7a33\u5b9a\u3002\u800c\u6570\u636e\u5e93\u7cfb\u7edf\u8ffd\u6c42\u7684\u662f\u53ef\u9884\u671f\u7684\u3001\u7a33\u5b9a\u7684\u6027\u80fd\u3002\u6b64\u5916\uff0c\u8df3\u8868\u7684\u6307\u9488\u4f1a\u5360\u7528\u66f4\u591a\u7684\u5185\u5b58\u7a7a\u95f4\u3002<\/li>\n\n\n\n<li><strong>\u5bf9\u6bd4B\u6811<\/strong>\uff1a\u8fd9\u624d\u662f\u771f\u6b63\u7684\u201c\u7ec8\u6781\u5bf9\u51b3\u201d\u3002B\u6811\u548cB+\u6811\u975e\u5e38\u76f8\u4f3c\uff0c\u6700\u5927\u7684\u533a\u522b\u5728\u4e8e\uff1a<strong>B\u6811\u7684\u975e\u53f6\u5b50\u8282\u70b9\u4e5f\u5b58\u50a8\u6570\u636e<\/strong>\u3002\u8fd9\u5e26\u6765\u4e86\u4e24\u4e2a\u81f4\u547d\u7684\u7f3a\u70b9\uff1a\n<ol>\n<li><strong>\u8303\u56f4\u67e5\u8be2\u6027\u80fd\u5dee<\/strong>\uff1a\u7531\u4e8e\u6570\u636e\u5206\u6563\u5728\u6240\u6709\u8282\u70b9\u4e2d\uff0c\u8fdb\u884c\u8303\u56f4\u67e5\u8be2\u65f6\uff0c\u53ef\u80fd\u9700\u8981\u8fdb\u884c\u590d\u6742\u7684\u4e2d\u5e8f\u904d\u5386\uff0c\u6548\u7387\u8fdc\u4e0d\u5982B+\u6811\u90a3\u6837\u6cbf\u7740\u53f6\u5b50\u8282\u70b9\u7684\u94fe\u8868\u4e00\u8def\u626b\u8fc7\u53bb\u6765\u5f97\u76f4\u63a5\u3002<\/li>\n\n\n\n<li><strong>\u5185\u5b58\u6548\u7387\u4f4e<\/strong>\uff1a\u56e0\u4e3a\u975e\u53f6\u5b50\u8282\u70b9\u5b58\u50a8\u4e86\u6570\u636e\uff0c\u5bfc\u81f4\u6bcf\u4e2a\u8282\u70b9\u80fd\u5bb9\u7eb3\u7684\u5173\u952e\u5b57\u6570\u91cf\u53d8\u5c11\uff0c\u6811\u7684\u9ad8\u5ea6\u4f1a\u76f8\u5e94\u589e\u52a0\u3002\u66f4\u91cd\u8981\u7684\u662f\uff0c\u8fd9\u4f7f\u5f97\u5c06\u6240\u6709\u975e\u53f6\u5b50\u8282\u70b9\uff08\u7d22\u5f15\u76ee\u5f55\uff09\u4e00\u6b21\u6027\u52a0\u8f7d\u5230\u5185\u5b58\u53d8\u5f97\u66f4\u52a0\u56f0\u96be\uff0c\u67e5\u8be2\u65f6\u5f88\u53ef\u80fd\u9700\u8981\u9891\u7e41\u5730\u8fdb\u884c\u78c1\u76d8I\/O\u6765\u8bfb\u53d6\u975e\u53f6\u5b50\u8282\u70b9\u3002<\/li>\n<\/ol>\n<\/li>\n<\/ul>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-large is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"478\" src=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-257-1024x478.png\" alt=\"\" class=\"wp-image-18978\" style=\"width:466px;height:auto\" srcset=\"https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-257-1024x478.png 1024w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-257-300x140.png 300w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-257-768x359.png 768w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-257-830x388.png 830w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-257-230x107.png 230w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-257-350x164.png 350w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-257-480x224.png 480w, https:\/\/92it.top\/wp-content\/uploads\/2025\/08\/image-257.png 1280w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/><\/figure><\/div>\n\n\n<p>\u7efc\u4e0a\u6240\u8ff0\uff0c\u4e00\u4e2a\u6570\u636e\u7ed3\u6784\u662f\u5426\u9002\u5408\u505a\u6570\u636e\u5e93\u7d22\u5f15\uff0c\u9700\u8981\u7efc\u5408\u8bc4\u4f30\u5176\u67e5\u8be2\u3001\u63d2\u5165\u3001\u5220\u9664\u7684\u6027\u80fd\uff0c\u4ee5\u53ca\u5bf9\u8303\u56f4\u67e5\u8be2\u7684\u652f\u6301\u548c\u5185\u5b58\u6d88\u8017\u3002B+\u6811\u6b63\u662f\u5728\u8fd9\u4e9b\u65b9\u9762\u53d6\u5f97\u4e86\u6700\u4f73\u7684\u5e73\u8861\u3002<\/p>\n\n\n\n<p><strong>2.2.2 \u4eae\u70b9\u4e8c\uff1a\u4e3a\u4f55\u6570\u636e\u5e93\u6709\u65f6\u4f1a\u201c\u65e0\u89c6\u201d\u7d22\u5f15\uff1f<\/strong><\/p>\n\n\n\n<p>\u6570\u636e\u5e93\u4f18\u5316\u5668\u662f\u4e00\u4e2a\u975e\u5e38\u201c\u806a\u660e\u201d\u7684\u51b3\u7b56\u8005\uff0c\u5b83\u7684\u552f\u4e00\u76ee\u6807\u662f\u627e\u5230\u6210\u672c\u6700\u4f4e\u7684\u67e5\u8be2\u8def\u5f84\u3002\u5728\u67d0\u4e9b\u60c5\u51b5\u4e0b\uff0c\u5b83\u4f1a\u8ba4\u4e3a\u5168\u8868\u626b\u63cf\uff08Full Table Scan\uff09\u6bd4\u8d70\u7d22\u5f15\u66f4\u5feb\uff0c\u4ece\u800c\u653e\u5f03\u4f7f\u7528\u7d22\u5f15\u3002<\/p>\n\n\n\n<p>\u4ee5\u4e0b\u662f\u51e0\u79cd\u5e38\u89c1\u7684\u60c5\u51b5\uff1a<\/p>\n\n\n\n<ul>\n<li><strong>\u4f7f\u7528\u4e86\u4e0d\u7b26\u5408\u7d22\u5f15\u89c4\u5219\u7684\u67e5\u8be2<\/strong>\uff1a\u4f8b\u5982\u5bf9\u7d22\u5f15\u5217\u4f7f\u7528 <code>!=<\/code>\u3001<code>&lt;&gt;<\/code>\uff0c\u6216\u8005 <code>LIKE '%keyword'<\/code> \u8fd9\u6837\u7684\u524d\u5bfc\u6a21\u7cca\u67e5\u8be2\u3002<\/li>\n\n\n\n<li><strong>\u5bf9\u7d22\u5f15\u5217\u8fdb\u884c\u51fd\u6570\u8fd0\u7b97\u6216\u8868\u8fbe\u5f0f\u8ba1\u7b97<\/strong>\uff1a\u4f8b\u5982 <code>WHERE YEAR(create_time) = 2025<\/code>\uff0c\u8fd9\u4f1a\u8ba9\u7d22\u5f15\u5931\u6548\u3002\u6b63\u786e\u7684\u505a\u6cd5\u662f\u6539\u5199\u4e3a <code>WHERE create_time &gt;= '2025-01-01' AND create_time &lt; '2026-01-01'<\/code>\u3002<\/li>\n\n\n\n<li><strong>\u7d22\u5f15\u5217\u7684\u533a\u5206\u5ea6\uff08Cardinality\uff09\u8fc7\u4f4e<\/strong>\uff1a\u6bd4\u5982\u4e00\u4e2a\u201c\u6027\u522b\u201d\u5217\uff0c\u53ea\u6709\u7537\u3001\u5973\u3001\u672a\u77e5\u4e09\u79cd\u503c\u3002\u5982\u679c\u7528\u5b83\u505a\u7d22\u5f15\uff0c\u6bcf\u6b21\u7b5b\u9009\u53ef\u80fd\u8fd8\u662f\u4f1a\u8fc7\u6ee4\u51fa1\/3\u7684\u6570\u636e\u3002\u4f18\u5316\u5668\u8ba4\u4e3a\uff0c\u4e0e\u5176\u8d70\u7d22\u5f15\u518d\u56de\u8868\u8fd9\u4e48\u591a\u6b21\uff0c\u8fd8\u4e0d\u5982\u76f4\u63a5\u626b\u63cf\u5168\u8868\u6765\u5f97\u5feb\u3002<\/li>\n\n\n\n<li><strong>\u6570\u636e\u91cf\u592a\u5c0f\uff0c\u6216\u67e5\u8be2\u7ed3\u679c\u96c6\u5360\u6bd4\u8fc7\u5927<\/strong>\uff1a\u5f53\u8868\u91cc\u7684\u6570\u636e\u603b\u5171\u5c31\u51e0\u767e\u884c\u65f6\uff0c\u4f18\u5316\u5668\u89c9\u5f97\u76f4\u63a5\u5168\u8868\u626b\u63cf\u7684\u6210\u672c\uff0c\u6bd4\u5148\u67e5\u7d22\u5f15\u518d\u56de\u8868\u7684\u6210\u672c\u8fd8\u8981\u4f4e\u3002\u540c\u7406\uff0c\u5982\u679c\u4f18\u5316\u5668\u4f30\u7b97\u51fa\u8d70\u7d22\u5f15\u540e\uff0c\u8fd8\u9700\u8981\u56de\u8868\u67e5\u8be2\u8868\u4e2d\u5927\u90e8\u5206\u7684\u6570\u636e\u884c\uff08\u6bd4\u5982\u8d85\u8fc720%~30%\uff09\uff0c\u5b83\u4e5f\u53ef\u80fd\u76f4\u63a5\u9009\u62e9\u5168\u8868\u626b\u63cf\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u8fd9\u91cc\u4f60\u53ef\u4ee5\u8865\u5145\u4e00\u53e5\uff0c\u867d\u7136\u53ef\u4ee5\u901a\u8fc7 <code>FORCE INDEX<\/code> \u8fd9\u6837\u7684SQL\u63d0\u793a\uff08Hint\uff09\u6765\u5f3a\u5236\u6570\u636e\u5e93\u4f7f\u7528\u67d0\u4e2a\u7d22\u5f15\uff0c\u4f46\u8fd9\u901a\u5e38\u662f\u6700\u540e\u7684\u624b\u6bb5\u3002\u6700\u4f73\u5b9e\u8df5\u8fd8\u662f\u5e94\u8be5\u901a\u8fc7\u4f18\u5316SQL\u548c\u7d22\u5f15\u8bbe\u8ba1\uff0c\u6765\u5f15\u5bfc\u4f18\u5316\u5668\u505a\u51fa\u6b63\u786e\u7684\u9009\u62e9\u3002<\/p>\n\n\n\n<p><strong>2.2.3 \u4eae\u70b9\u4e09\uff1a\u7d22\u5f15\u4e0eNULL\u7684\u5fae\u5999\u5173\u7cfb<\/strong><\/p>\n\n\n\n<p>\u5173\u4e8e\u201c\u5217\u4e2d\u542b\u6709NULL\u503c\uff0c\u7d22\u5f15\u4f1a\u5931\u6548\u201d\u7684\u8bf4\u6cd5\uff0c\u5728\u793e\u533a\u4e2d\u6d41\u4f20\u5f88\u5e7f\uff0c\u4f46\u8fd9\u4e2a\u8bf4\u6cd5\u5e76<strong>\u4e0d\u5b8c\u5168\u51c6\u786e<\/strong>\u3002<\/p>\n\n\n\n<p>\u5728MySQL\u7684InnoDB\u5f15\u64ce\u4e2d\uff0c\u4f60\u9700\u8981\u77e5\u9053\u4e24\u70b9\uff1a<\/p>\n\n\n\n<ol>\n<li><strong>MySQL\u53ef\u4ee5\u4e3a\u5305\u542bNULL\u503c\u7684\u5217\u521b\u5efa\u7d22\u5f15\uff0c\u5e76\u4e14\u80fd\u591f\u4f7f\u7528\u8be5\u7d22\u5f15<\/strong>\u3002\u65e0\u8bba\u662f <code>IS NULL<\/code> \u8fd8\u662f <code>IS NOT NULL<\/code> \u7684\u67e5\u8be2\uff0c\u90fd\u53ef\u4ee5\u6b63\u5e38\u5730\u5229\u7528\u5230\u7d22\u5f15\u3002<\/li>\n\n\n\n<li><strong>\u552f\u4e00\u7d22\u5f15\uff08Unique Index\uff09\u5141\u8bb8\u5b58\u5728\u591a\u4e2aNULL\u503c<\/strong>\u3002\u8fd9\u662f\u56e0\u4e3a\u5728SQL\u6807\u51c6\u4e2d\uff0c<code>NULL<\/code> \u548c\u4efb\u4f55\u503c\uff08\u5305\u62ec\u53e6\u4e00\u4e2a <code>NULL<\/code>\uff09\u8fdb\u884c\u6bd4\u8f83\uff0c\u7ed3\u679c\u90fd\u662f\u672a\u77e5\u7684\uff08unknown\uff09\uff0c\u6240\u4ee5\u591a\u4e2a<code>NULL<\/code>\u5e76\u4e0d\u4f1a\u8fdd\u53cd\u552f\u4e00\u6027\u7ea6\u675f\u3002<\/li>\n<\/ol>\n\n\n\n<p>\u5c3d\u7ba1\u5982\u6b64\uff0c\u5728\u8868\u8bbe\u8ba1\u4e2d\uff0c\u6211\u4eec\u4f9d\u7136\u63a8\u8350\u4f7f\u7528\u4e00\u4e2a\u6709\u4e1a\u52a1\u542b\u4e49\u7684\u9ed8\u8ba4\u503c\uff08\u59820\u3001-1\u3001\u7a7a\u5b57\u7b26\u4e32\u7b49\uff09\u6765\u4ee3\u66ff<code>NULL<\/code>\uff0c\u5e76\u5c06\u5217\u8bbe\u7f6e\u4e3a <code>NOT NULL<\/code>\u3002\u8fd9\u662f\u4e00\u79cd\u66f4\u4f73\u7684\u5b9e\u8df5\uff0c\u53ef\u4ee5\u907f\u514d\u5728\u5e94\u7528\u5c42\u5904\u7406<code>NULL<\/code>\u65f6\u53ef\u80fd\u5e26\u6765\u7684\u5404\u79cd\u903b\u8f91\u6df7\u6dc6\u548c\u6f5c\u5728\u7684bug\u3002<\/p>\n\n\n\n<p>\u3000<\/p>\n\n\n\n<p><strong>3. \u6838\u5fc3\u8981\u70b9\u56de\u987e<\/strong><\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p>\u8fd9\u7bc7\u6587\u7ae0\uff0c\u6211\u4eec\u6df1\u5165\u63a2\u8ba8\u4e86\u6570\u636e\u5e93\u7d22\u5f15\u7684\u6838\u5fc3\u539f\u7406\u3002\u4f60\u9700\u8981\u91cd\u70b9\u638c\u63e1B+\u6811\u7684\u6570\u636e\u7ed3\u6784\u3001\u805a\u7c07\u7d22\u5f15\u4e0e\u975e\u805a\u7c07\u7d22\u5f15\u7684\u533a\u522b\u3001\u56de\u8868\u7684\u6982\u5ff5\uff0c\u4ee5\u53ca\u6700\u5de6\u5339\u914d\u539f\u5219\u7684\u8fd0\u4f5c\u673a\u5236\u3002<\/p>\n\n\n\n<p>\u8981\u60f3\u5728\u9762\u8bd5\u4e2d\u8131\u9896\u800c\u51fa\uff0c\u4f60\u9700\u8981\u4ece\u4ee5\u4e0b\u51e0\u4e2a\u65b9\u9762\u4e0b\u529f\u592b\uff0c\u5c55\u73b0\u4f60\u7684\u601d\u8003\u6df1\u5ea6\uff1a<\/p>\n\n\n\n<ul>\n<li><strong>MySQL\u4e3a\u4f55\u9009\u62e9B+\u6811\uff1f<\/strong> \u80fd\u5426\u4eceI\/O\u6210\u672c\u3001\u8303\u56f4\u67e5\u8be2\u3001\u5185\u5b58\u6548\u7387\u7b49\u591a\u4e2a\u7ef4\u5ea6\uff0c\u5bf9\u6bd4\u5206\u6790\u4e0d\u540c\u6570\u636e\u7ed3\u6784\u7684\u4f18\u52a3\u3002<\/li>\n\n\n\n<li><strong>\u6570\u636e\u5e93\u4e3a\u4f55\u4f1a\u653e\u5f03\u4f7f\u7528\u7d22\u5f15\uff1f<\/strong> \u80fd\u5426\u7ad9\u5728\u6570\u636e\u5e93\u4f18\u5316\u5668\u7684\u89d2\u5ea6\uff0c\u53bb\u7406\u89e3\u5176\u6210\u672c\u4f30\u7b97\u7684\u51b3\u7b56\u8fc7\u7a0b\u3002<\/li>\n\n\n\n<li><strong>\u7d22\u5f15\u4e0eNULL\u7684\u5173\u7cfb\uff1f<\/strong> 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