{"id":16298,"date":"2024-09-10T11:03:29","date_gmt":"2024-09-10T03:03:29","guid":{"rendered":"https:\/\/92it.top\/?p=16298"},"modified":"2024-09-10T15:24:44","modified_gmt":"2024-09-10T07:24:44","slug":"%e7%90%86%e8%a7%a3-mysql-%e7%b4%a2%e5%bc%95%e5%8e%9f%e7%90%86%e5%8f%8a%e7%89%b9%e6%80%a7","status":"publish","type":"post","link":"https:\/\/92it.top\/?p=16298","title":{"rendered":"\u7406\u89e3 Mysql \u7d22\u5f15\u539f\u7406\u53ca\u7279\u6027"},"content":{"rendered":"\n

\u8f6c\u8f7d\uff1ahttps:\/\/my.oschina.net\/u\/4090830\/blog\/10320986<\/p>\n\n\n\n

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\u5728\u6570\u636e\u5e93\u4e2d\uff0c\u7d22\u5f15(Index)\u662f\u4e00\u79cd\u6570\u636e\u7ed3\u6784\uff0c\u5b83\u80fd\u591f\u5feb\u901f\u5730\u5b9a\u4f4d\u5230\u8868\u4e2d\u7684\u7279\u5b9a\u884c\u6216\u8bb0\u5f55\u3002\u7d22\u5f15\u901a\u5e38\u662f\u5728\u8868\u4e0a\u7684\u4e00\u7ec4\u5217\u4e0a\u521b\u5efa\u7684\uff0c\u8fd9\u4e9b\u5217\u53ef\u4ee5\u662f\u8868\u7684\u4e3b\u952e\u3001\u552f\u4e00\u952e\u6216\u5176\u4ed6\u91cd\u8981\u7684\u5217\u3002\u901a\u8fc7\u5728\u8fd9\u4e9b\u5217\u4e0a\u521b\u5efa\u7d22\u5f15\uff0c\u53ef\u4ee5\u63d0\u9ad8\u6570\u636e\u5e93\u7684\u67e5\u8be2\u6027\u80fd\u548c\u6570\u636e\u68c0\u7d22\u901f\u5ea6\u3002<\/p>\n\n\n\n

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1.\u7d22\u5f15\u5982\u4f55\u5de5\u4f5c\uff0c\u662f\u5982\u4f55\u52a0\u5feb\u67e5\u8be2\u901f\u5ea6<\/strong><\/p>\n\n\n\n

\n\n\n\n

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1\uff09\u6ca1\u6709\u7d22\u5f15\u7684\u60c5\u51b5\u4e0b\u8bbf\u95ee\u6570\u636e\uff1a<\/strong><\/p>\n\n\n

\n
\"\"<\/figure><\/div>\n\n\n

2\uff09\u4f7f\u7528\u5e73\u8861\u4e8c\u53c9\u6811\u7ed3\u6784\u7d22\u5f15\u7684\u60c5\u51b5\u4e0b\u8bbf\u95ee\u6570\u636e\uff1a<\/strong><\/p>\n\n\n

\n
\"\"<\/figure><\/div>\n\n\n

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2.\u7d22\u5f15\u7684\u7ec4\u6210\u90e8\u5206\u548c\u79cd\u7c7b<\/strong><\/p>\n\n\n\n

\n\n\n\n

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2.1 hash<\/strong><\/p>\n\n\n\n

hash \u601d\u8def\u7b80\u5355\uff0c\u5c31\u662f\u628a\u6211\u4eec\u63d2\u5165\u7684 key \u901a\u8fc7 hash \u51fd\u6570\u7b97\u6cd5 (\u4ee5\u524d\u4e00\u822c\u662f\u53d6\u4f59\u6570\uff0c\u5c31\u597d\u6bd4 hashmap \u7684\u8ba1\u7b97\u65b9\u5f0f\u79fb\u4f4d\u5f02\u6216\u4e4b\u7c7b\u7684)\uff0c\u8ba1\u7b97\u51fa\u5bf9\u5e94\u7684 value\uff0c\u628a\u8fd9\u4e2a value \u653e\u5230\u4e00\u4e2a\u4f4d\u7f6e\uff0c\u8fd9\u4e2a\u4f4d\u7f6e\u53eb\u505a\u54c8\u5e0c\u69fd\u3002\u5bf9\u5e94\u78c1\u76d8\u4f4d\u7f6e\u6307\u9488\u653e\u5165 hash \u69fd\u91cc\u9762\u3002\u4e00\u53e5\u8bdd\u603b\u7ed3 hash \u7d22\u5f15\uff0c\u5c31\u662f\u5b58\u50a8\u4e86\u7d22\u5f15\u5b57\u6bb5\u7684 hash \u503c\u548c\u6570\u636e\u6240\u5728\u78c1\u76d8\u6587\u4ef6\u6307\u9488\u3002<\/p>\n\n\n\n

\u4f46\u662f\u4e0d\u53ef\u907f\u514d\u7684\u662f\uff0c\u65e0\u8bba\u4ec0\u4e48\u7b97\u6cd5\uff0c\u6570\u636e\u91cf\u5927\u4e86\u4e4b\u540e\u96be\u514d\u4f1a\u51fa\u73b0\u4e0d\u540c\u7684\u6570\u636e\u88ab\u653e\u5728\u4e00\u4e2a hash \u69fd\u91cc\u9762\u3002\u6bd4\u5982\u5b57\u5178\u4e0a\u7684 \u201c\u5434\u201d \u548c\u201d \u6b66\u201d \u5c31\u662f\u540c\u97f3\uff0c\u4f60\u67e5\u5b57\u5178\u7684\u65f6\u5019\u5230\u8fd9\u91cc\u53ea\u80fd\u987a\u5e8f\u5f80\u4e0b\u53bb\u627e\u4e86\u3002\u7d22\u5f15\u7684\u5904\u7406\u4e5f\u662f\u8fd9\u6837\uff0c\u4f1a\u62c9\u51fa\u4e00\u4e2a\u94fe\u8868\uff0c\u9700\u8981\u7684\u65f6\u5019\u987a\u5e8f\u904d\u5386\u5373\u53ef\u3002<\/p>\n\n\n

\n
\"\"<\/figure><\/div>\n\n\n
    \n
  • \u7f3a\u70b9\uff1a\u65e0\u5e8f\u7d22\u5f15\uff0c\u533a\u95f4\u67e5\u8be2\u6027\u80fd\u4f4e\uff0c\u56e0\u4e3a\u533a\u95f4\u67e5\u8be2\u4f1a\u9020\u6210\u591a\u6b21\u8bbf\u95ee\u78c1\u76d8\uff0c\u591a\u6b21 io \u8017\u65f6\u662f\u5f88\u96be\u63a5\u53d7\u7684\u3002<\/li>\n\n\n\n
  • \u4f18\u70b9\uff1ainsert \u8fc5\u901f\uff0c\u53ea\u9700\u5f80\u540e\u8865\u5c31\u884c<\/li>\n\n\n\n
  • \u573a\u666f\uff1a\u7b49\u503c\u67e5\u8be2\uff0c \u6bd4\u5982 memcached \u3002\u4e0d\u9002\u7528\u5927\u91cf\u91cd\u590d\u6570\u636e\u7684\u5217\uff0c\u907f\u514d hash \u51b2\u7a81<\/li>\n\n\n\n
  • \u603b\u7ed3\uff1a\u60f3\u6210 java \u7684 hashmap \u5373\u53ef<\/li>\n<\/ul>\n\n\n\n

    2.2 \u6709\u5e8f\u6570\u7ec4<\/strong><\/p>\n\n\n\n

    \u5982\u679c\u6211\u4eec\u9700\u8981\u533a\u95f4\u67e5\u8be2\u7684\u65f6\u5019\uff0chash \u7d22\u5f15\u7684\u6027\u80fd\u5c31\u4e0d\u5c3d\u5982\u4eba\u610f\u4e86\u3002\u8fd9\u4e2a\u65f6\u5019\u6709\u5e8f\u6570\u7ec4\u7684\u4f18\u52bf\u5c31\u80fd\u4f53\u73b0\u51fa\u6765\u4e86\u3002<\/p>\n\n\n\n

    \u5f53\u6211\u4eec\u9700\u8981\u4ece\u4e00\u4e2a\u6709\u5e8f\u6570\u7ec4\u91cc\u53d6 A \u548c B \u4e4b\u95f4\u7684\u503c\u65f6\uff0c\u53ea\u9700\u8981\u901a\u8fc7\u4e8c\u5206\u6cd5\u5b9a\u4f4d\u5230 A \u7684\u4f4d\u7f6e\uff0c\u65f6\u95f4\u590d\u6742\u5ea6 O (log (N)), \u63a5\u7740\u4ece A \u904d\u5386\u5230 B \u5373\u53ef\uff0c\u8bba\u901f\u5ea6\u7684\u8bdd\uff0c\u57fa\u672c\u4e0a\u53ef\u4ee5\u8bf4\u662f\u6700\u5feb\u7684\u4e86\u3002\u4f46\u662f\u5f53\u6211\u4eec\u9700\u8981\u66f4\u65b0\u7684\u65f6\u5019\uff0c\u9700\u8981\u8fdb\u884c\u7684\u64cd\u4f5c\u5c31\u5f88\u591a\u4e86\u3002\u5982\u679c\u9700\u8981\u63d2\u5165\u4e00\u6761\u6570\u636e\uff0c\u4f60\u9700\u8981\u632a\u52a8\u6570\u636e\u4e4b\u540e\u7684\u6240\u6709\u6570\u636e\uff0c\u6d6a\u8d39\u6027\u80fd\u3002\u6240\u4ee5\u603b\u7ed3\u6765\u8bf4\uff0c\u53ea\u6709\u4e0d\u600e\u4e48\u53d8\u5316\u7684\u6570\u636e\u9002\u5408\u6709\u5e8f\u6570\u7ec4\u7ed3\u6784\u7684\u7d22\u5f15\u3002<\/p>\n\n\n\n

      \n
    • \u7f3a\u70b9\uff1ainsert \u65b0\u6570\u636e\u7684\u65f6\u5019\uff0c\u9700\u8981\u6539\u53d8\u540e\u7eed\u6240\u6709\u6570\u636e\uff0c\u6210\u672c\u7565\u9ad8\u3002<\/li>\n\n\n\n
    • \u4f18\u70b9\uff1a\u67e5\u8be2\u901f\u5ea6\u5f88\u5feb\uff0c\u7406\u8bba\u6700\u5927\u503c\u3002<\/li>\n\n\n\n
    • \u573a\u666f\uff1a\u5f52\u6863\u67e5\u8be2\uff0c\u65e5\u5fd7\u67e5\u8be2\u7b49\u6781\u5c11\u53d8\u5316\u7684<\/li>\n\n\n\n
    • \u603b\u7ed3\uff1a\u5c31\u662f\u987a\u5e8f\u6392\u7684\u6570\u7ec4<\/li>\n<\/ul>\n\n\n\n

      2.3 \u4e8c\u53c9\u641c\u7d22\u6811<\/strong><\/p>\n\n\n\n

      \u57fa\u672c\u539f\u5219\u662f\u6811\u7684\u5de6\u8282\u70b9\u90fd\u5c0f\u4e8e\u7236\u8282\u70b9\uff0c\u53f3\u8282\u70b9\u90fd\u5927\u4e8e\u7236\u8282\u70b9<\/p>\n\n\n

      \n
      \"\"<\/figure><\/div>\n\n\n

      \u8fd9\u91cc\u6211\u4eec\u5c31\u80fd\u770b\u51fa\u6765\uff0c\u4e8c\u53c9\u641c\u7d22\u6811\u7684\u67e5\u8be2\u6548\u7387\u539f\u5219\u4e0a\u662f O (log (N))\uff0c\u4e3a\u4e86\u4fdd\u8bc1\u662f\u5e73\u8861\u4e8c\u53c9\u6811\uff0c\u66f4\u65b0\u6548\u7387\u4e5f\u662f O (log (N))\u3002\u4f46\u662f\u6570\u636e\u5f88\u591a\u7684\u60c5\u51b5\u6811\u7684\u9ad8\u5ea6\u4f1a\u8fbe\u5230\u5f88\u9ad8\uff0c\u8fc7\u591a\u6b21\u8bbf\u95ee\u78c1\u76d8\uff0c\u662f\u4e0d\u53ef\u53d6\u7684\u3002\u5e76\u4e14\u6781\u7aef\u60c5\u51b5\u4e0b\uff0c\u6811\u9000\u5316\u6210\u94fe\u8868\uff0c\u67e5\u8be2\u7684\u590d\u6742\u5ea6\u4f1a\u88ab\u62c9\u6210 O (n)\u3002<\/p>\n\n\n\n

      \u8fdb\u5316\u6210\u591a\u53c9\u6811\uff0c\u4e5f\u5c31\u662f\u591a\u4e2a\u5b50\u8282\u70b9\u7684\u65f6\u5019\uff0c\u4f1a\u5927\u5927\u7684\u51cf\u5c11\u6811\u7684\u9ad8\u5ea6\uff0c\u964d\u4f4e\u8bbf\u95ee\u78c1\u76d8\u3002<\/p>\n\n\n\n

        \n
      • \u7f3a\u70b9\uff1a\u6570\u636e\u91cf\u5927\u7684\u65f6\u5019\uff0c\u6811\u4f1a\u8fc7\u9ad8\uff0c\u5bfc\u81f4\u591a\u6b21\u8bbf\u95ee\u78c1\u76d8<\/li>\n\n\n\n
      • \u4f18\u70b9\uff1a\u8fdb\u5316\u6210\u591a\u53c9\u6811\uff0c\u4f1a\u964d\u4f4e\u6811\u9ad8\uff0c\u8bbf\u95ee\u78c1\u76d8\u6b21\u6570\u3002<\/li>\n\n\n\n
      • \u573a\u666f\uff1a\u9002\u7528\u5f88\u591a\u573a\u666f<\/li>\n\n\n\n
      • \u603b\u7ed3\uff1a\u5de6\u5c0f\u53f3\u5927\u7684\u6811<\/li>\n<\/ul>\n\n\n\n

        2.4 B \u6811<\/strong><\/p>\n\n\n\n

        \u5728\u6bcf\u4e2a\u8282\u70b9\u5b58\u50a8\u591a\u4e2a\u5143\u7d20\uff0c\u5728\u6bcf\u4e2a\u8282\u70b9\u5c3d\u53ef\u80fd\u591a\u7684\u5b58\u50a8\u6570\u636e\u3002\u6bcf\u4e2a\u8282\u70b9\u53ef\u4ee5\u5b58\u50a8 1000 \u4e2a\u7d22\u5f15\uff0816k\/16=1000\uff09\uff0c\u8fd9\u6837\u5c31\u5c06\u4e8c\u53c9\u6811\u6539\u9020\u6210\u4e86\u591a\u53c9\u6811\uff0c\u901a\u8fc7\u589e\u52a0\u6811\u7684\u53c9\u6811\uff0c\u5c06\u6811\u4ece\u9ad8\u7626\u53d8\u4e3a\u77ee\u80d6\u3002\u6784\u5efa 1 \u767e\u4e07\u6761\u6570\u636e\uff0c\u6811\u7684\u9ad8\u5ea6\u53ea\u9700\u8981 2 \u5c42\u5c31\u53ef\u4ee5\uff081000*1000=1 \u767e\u4e07\uff09\uff0c\u4e5f\u5c31\u662f\u8bf4\u53ea\u9700\u8981 2 \u6b21\u78c1\u76d8 IO \u5c31\u53ef\u4ee5\u67e5\u8be2\u5230\u6570\u636e\u3002\u78c1\u76d8 IO \u6b21\u6570\u53d8\u5c11\u4e86\uff0c\u67e5\u8be2\u6570\u636e\u7684\u6548\u7387\u4e5f\u5c31\u63d0\u9ad8\u4e86\u3002<\/p>\n\n\n\n

        \u8fd9\u79cd\u6570\u636e\u7ed3\u6784\u6211\u4eec\u79f0\u4e3a B \u6811\uff0cB \u6811\u662f\u4e00\u79cd\u591a\u53c9\u5e73\u8861\u67e5\u627e\u6811<\/p>\n\n\n\n

        2.5 B + \u6811<\/strong><\/p>\n\n\n\n

        B + \u6811\u548c B \u6811\u6700\u4e3b\u8981\u7684\u533a\u522b\u5728\u4e8e\u975e\u53f6\u5b50\u8282\u70b9\u662f\u5426\u5b58\u50a8\u6570\u636e\u7684\u95ee\u9898\u3002<\/p>\n\n\n\n

          \n
        • B \u6811\uff1a\u975e\u53f6\u5b50\u8282\u70b9\u548c\u53f6\u5b50\u8282\u70b9\u90fd\u4f1a\u5b58\u50a8\u6570\u636e\u3002<\/li>\n\n\n\n
        • B + \u6811\uff1a\u53ea\u6709\u53f6\u5b50\u8282\u70b9\u624d\u4f1a\u5b58\u50a8\u6570\u636e\uff0c\u975e\u53f6\u5b50\u8282\u70b9\u81f3\u5b58\u50a8\u952e\u503c\u3002\u53f6\u5b50\u8282\u70b9\u4e4b\u95f4\u4f7f\u7528\u53cc\u5411\u6307\u9488\u8fde\u63a5\uff0c\u6700\u5e95\u5c42\u7684\u53f6\u5b50\u8282\u70b9\u5f62\u6210\u4e86\u4e00\u4e2a\u53cc\u5411\u6709\u5e8f\u94fe\u8868\u3002<\/li>\n<\/ul>\n\n\n
          \n
          \"\"<\/figure><\/div>\n\n\n

          \u6b63\u662f\u56e0\u4e3a B + \u6811\u7684\u53f6\u5b50\u8282\u70b9\u662f\u901a\u8fc7\u94fe\u8868\u8fde\u63a5\u7684\uff0c\u6240\u4ee5\u627e\u5230\u4e0b\u9650\u540e\u80fd\u5f88\u5feb\u8fdb\u884c\u533a\u95f4\u67e5\u8be2\uff0c\u6bd4\u6b63\u5e38\u7684\u4e2d\u5e8f\u904d\u5386\u5feb<\/p>\n\n\n\n

          3.\u7d22\u5f15\u7684\u7ef4\u62a4<\/strong><\/p>\n\n\n\n

          \n\n\n\n

          \u5f53\u4f60 insert \u4e00\u6761\u6570\u636e\u7684\u65f6\u5019\uff0c\u7d22\u5f15\u9700\u8981\u505a\u51fa\u5fc5\u8981\u7684\u64cd\u4f5c\u6765\u4fdd\u8bc1\u6570\u636e\u7684\u6709\u5e8f\u578b\u3002\u4e00\u822c\u81ea\u589e\u6570\u636e\u76f4\u63a5\u5728\u540e\u9762\u52a0\u5c31\u884c\u4e86\uff0c\u7279\u6b8a\u60c5\u51b5\u4e0b\u5982\u679c\u6570\u636e\u52a0\u5230\u4e86\u4e2d\u95f4\uff0c\u5c31\u9700\u8981\u632a\u52a8\u540e\u9762\u6240\u6709\u7684\u6570\u636e\uff0c\u8fd9\u6837\u6548\u7387\u6bd4\u8f83\u53d7\u5f71\u54cd\u3002<\/p>\n\n\n\n

          \u6700\u7cdf\u7cd5\u7684\u60c5\u51b5\uff0c\u5982\u679c\u5f53\u524d\u7684\u6570\u636e\u9875\uff08\u9875\u662f mysql \u5b58\u50a8\u7684\u6700\u5c0f\u5355\u4f4d\uff09\u5b58\u6ee1\u4e86\uff0c\u9700\u8981\u7533\u8bf7\u4e00\u4e2a\u65b0\u7684\u6570\u636e\u9875\uff0c\u8fd9\u4e2a\u8fc7\u7a0b\u88ab\u79f0\u4e3a\u9875\u5206\u88c2\u3002\u5982\u679c\u9020\u6210\u4e86\u9875\u5206\u88c2\u7684\u8bdd\uff0c\u52bf\u5fc5\u4f1a\u9020\u6210\u6027\u80fd\u7684\u5f71\u54cd\u3002\u4f46\u662f mysql \u5e76\u4e0d\u662f\u65e0\u8111\u7684\u6570\u636e\u5206\u88c2\uff0c\u5982\u679c\u4f60\u662f\u4ece\u4e2d\u95f4\u8fdb\u884c\u6570\u636e\u5206\u88c2\u7684\u8bdd\uff0c\u5bf9\u4e8e\u81ea\u589e\u4e3b\u952e\uff0c\u4f1a\u5bfc\u81f4\u4e00\u534a\u7684\u6027\u80fd\u6d6a\u8d39\u3002mysql \u4f1a\u6839\u636e\u4f60\u7684\u7d22\u5f15\u7684\u7c7b\u578b\uff0c\u548c\u8ffd\u8e2a\u63d2\u5165\u6570\u636e\u7684\u60c5\u51b5\u51b3\u5b9a\u5206\u88c2\u7684\u65b9\u5f0f\uff0c\u4e00\u822c\u90fd\u5b58\u5728 mysql \u6570\u636e\u9875\u7684 head \u91cc\u9762\uff0c\u5982\u679c\u662f\u96f6\u6563\u7684\u63d2\u5165\uff0c\u4f1a\u4ece\u4e2d\u95f4\u5206\u88c2\u3002\u5982\u679c\u662f\u987a\u5e8f\u63d2\u5165\uff0c\u4e00\u822c\u662f\u4f1a\u9009\u62e9\u63d2\u5165\u70b9\u5f00\u59cb\u5206\u88c2\uff0c\u6216\u8005\u63d2\u5165\u70b9\u5f80\u540e\u51e0\u884c\u5bfc\u81f4\u7684\u3002\u51b3\u5b9a\u662f\u5426\u4ece\u4e2d\u95f4\u5206\u88c2\uff0c\u8fd8\u662f\u4ece\u6700\u540e\u5206\u88c2\u3002<\/p>\n\n\n

          \n
          \"\"<\/figure><\/div>\n\n\n

          \u5982\u679c\u63d2\u5165\u7684\u662f\u4e0d\u89c4\u5219\u7684\u6570\u636e\uff0c\u6ca1\u6cd5\u4fdd\u8bc1\u540e\u4e00\u4e2a\u503c\u6bd4\u524d\u4e00\u4e2a\u5927\uff0c\u5c31\u4f1a\u89e6\u53d1\u4e0a\u9762\u8bf4\u7684\u5206\u88c2\u903b\u8f91\uff0c\u6700\u540e\u8fbe\u5230\u4e0b\u9762\u7684\u6548\u679c<\/p>\n\n\n

          \n
          \"\"<\/figure><\/div>\n\n\n

          \u6240\u4ee5\u7edd\u5927\u591a\u6570\u60c5\u51b5\u4e0b\uff0c\u6211\u4eec\u90fd\u9700\u8981\u4f7f\u7528\u81ea\u589e\u7d22\u5f15\uff0c\u9664\u975e\u9700\u8981\u4e1a\u52a1\u81ea\u5b9a\u4e49\u4e3b\u952e\uff0c\u6700\u597d\u80fd\u4fdd\u8bc1\u53ea\u6709\u4e00\u4e2a\u7d22\u5f15\uff0c\u4e14\u7d22\u5f15\u662f\u552f\u4e00\u7d22\u5f15\u3002\u8fd9\u6837\u53ef\u4ee5\u907f\u514d\u56de\u8868\uff0c\u5bfc\u81f4\u67e5\u8be2\u641c\u7d22\u4e24\u68f5\u6811\u3002\u4fdd\u8bc1\u6570\u636e\u9875\u7684\u6709\u5e8f\u6027\uff0c\u53ef\u4ee5\u66f4\u597d\u7684\u4f7f\u7528\u7d22\u5f15\u3002<\/p>\n\n\n\n

          4.\u56de\u8868<\/strong><\/p>\n\n\n\n

          \n\n\n\n

          \u901a\u4fd7\u7684\u8bb2\u5c31\u662f\uff0c\u5982\u679c\u7d22\u5f15\u7684\u5217\u5728 select \u6240\u9700\u83b7\u5f97\u7684\u5217\u4e2d\uff08\u56e0\u4e3a\u5728 mysql \u4e2d\u7d22\u5f15\u662f\u6839\u636e\u7d22\u5f15\u5217\u7684\u503c\u8fdb\u884c\u6392\u5e8f\u7684\uff0c\u6240\u4ee5\u7d22\u5f15\u8282\u70b9\u4e2d\u5b58\u5728\u8be5\u5217\u4e2d\u7684\u90e8\u5206\u503c\uff09\u6216\u8005\u6839\u636e\u4e00\u6b21\u7d22\u5f15\u67e5\u8be2\u5c31\u80fd\u83b7\u5f97\u8bb0\u5f55\u5c31\u4e0d\u9700\u8981\u56de\u8868\uff0c\u5982\u679c select \u6240\u9700\u83b7\u5f97\u5217\u4e2d\u6709\u5927\u91cf\u7684\u975e\u7d22\u5f15\u5217\uff0c\u7d22\u5f15\u5c31\u9700\u8981\u5148\u627e\u5230\u4e3b\u952e\uff0c\u518d\u5230\u8868\u4e2d\u627e\u5230\u76f8\u5e94\u7684\u5217\u7684\u4fe1\u606f\uff0c\u8fd9\u5c31\u53eb\u56de\u8868\u3002<\/p>\n\n\n\n

          \u8981\u4ecb\u7ecd\u56de\u8868\u81ea\u7136\u5c31\u5f97\u4ecb\u7ecd\u805a\u96c6\u7d22\u5f15\u548c\u975e\u805a\u96c6\u7d22\u5f15
          InnoDB \u805a\u96c6\u7d22\u5f15\u7684\u53f6\u5b50\u8282\u70b9\u5b58\u50a8\u884c\u8bb0\u5f55\uff0c\u56e0\u6b64\uff0c InnoDB \u5fc5\u987b\u8981\u6709\uff0c\u4e14\u53ea\u6709\u4e00\u4e2a\u805a\u96c6\u7d22\u5f15\uff1a<\/p>\n\n\n\n

            \n
          • \u5982\u679c\u8868\u5b9a\u4e49\u4e86\u4e3b\u952e\uff0c\u5219 PK \u5c31\u662f\u805a\u96c6\u7d22\u5f15\uff1b<\/li>\n\n\n\n
          • \u5982\u679c\u8868\u6ca1\u6709\u5b9a\u4e49\u4e3b\u952e\uff0c\u5219\u7b2c\u4e00\u4e2a\u975e\u7a7a\u552f\u4e00\u7d22\u5f15\uff08not NULL unique\uff09\u5217\u662f\u805a\u96c6\u7d22\u5f15\uff1b<\/li>\n\n\n\n
          • \u5426\u5219\uff0cInnoDB \u4f1a\u521b\u5efa\u4e00\u4e2a\u9690\u85cf\u7684 row-id \u4f5c\u4e3a\u805a\u96c6\u7d22\u5f15\uff1b<\/li>\n<\/ul>\n\n\n
            \n
            \"\"<\/figure><\/div>\n\n\n

            5.\u7d22\u5f15\u8986\u76d6<\/strong><\/p>\n\n\n\n

            \n\n\n\n

            \u4e00\u53e5\u8bdd\u8868\u8fbe\u7684\u8bdd\uff0c\u662f\u53ea\u9700\u8981\u5728\u4e00\u68f5\u7d22\u5f15\u6811\u4e0a\u5c31\u80fd\u83b7\u53d6 SQL \u6240\u9700\u7684\u6240\u6709\u5217\u6570\u636e\uff0c\u65e0\u9700\u56de\u8868\uff0c\u901f\u5ea6\u66f4\u5feb\u3002\u843d\u5b9e\u5230 sql \u4e0a\u7684\u8bdd\uff0c\u53ea\u8981\u6267\u884c\u8ba1\u5212\u91cc\u9762\u7684\u8f93\u51fa\u7ed3\u679c Extra \u5b57\u6bb5\u4e3a Using index \u65f6\uff0c\u80fd\u591f\u89e6\u53d1\u7d22\u5f15\u8986\u76d6\u3002<\/p>\n\n\n\n

            \u5e38\u89c1\u7684\u4f18\u5316\u624b\u6bb5\uff0c\u5c31\u662f\u4e0a\u9762\u63d0\u5230\u7684\uff0c\u5c06\u67e5\u8be2\u7684\u5b57\u6bb5\u90fd\u5efa\u5230\u7d22\u5f15\u91cc\u9762\uff0c\u81f3\u4e8e dba \u613f\u4e0d\u613f\u610f\u8ba9\u4f60\u5efa\uff0c\u90a3\u5c31\u9700\u8981\u4f60\u4eec\u81ea\u5df1 battle \u4e86\u3002<\/p>\n\n\n\n

            \u4e00\u822c\u7d22\u5f15\u8986\u76d6\u9002\u7528\u7684\u573a\u666f\u5305\u62ec \u5168\u8868 count \u67e5\u8be2\u4f18\u5316\u3001\u5217\u67e5\u8be2\u56de\u8868\u3001\u5206\u9875\u56de\u8868\u3002\u9ad8\u7248\u672c\u7684 mysql \u5df2\u7ecf\u505a\u4e86\u4f18\u5316\uff0c\u5f53\u547d\u4e2d\u8054\u5408\u7d22\u5f15\u7684\u5176\u4e2d\u4e00\u4e2a\u5b57\u6bb5\uff0c\u53e6\u5916\u4e00\u4e2a\u662f id \u7684\u65f6\u5019\uff0c\u4f1a\u81ea\u52a8\u4f18\u5316\uff0c\u65e0\u9700\u56de\u8868\u3002\u56e0\u4e3a\u4e8c\u7ea7\u7d22\u5f15\u7684\u53f6\u5b50\u4e0a\u5b58\u4e86 primary key\uff0c\u4e5f\u7b97\u7d22\u5f15\u8986\u76d6\uff0c\u65e0\u9700\u989d\u5916\u6210\u672c\u3002<\/p>\n\n\n

            \n
            \"\"<\/figure><\/div>\n\n\n

            6.\u6700\u5de6\u5339\u914d\u539f\u5219<\/strong><\/p>\n\n\n\n

            \n\n\n\n

            \u7b80\u5355\u6765\u8bf4\uff0c\u5c31\u662f\u4f60\u4f7f\u7528 \u2018xx%\u2019\u7684\u65f6\u5019\uff0c\u7b26\u5408\u6761\u4ef6\u7684\u8bdd\u4e5f\u4f1a\u4f7f\u7528\u7d22\u5f15\u3002
            \u5982\u679c\u662f\u8054\u5408\u7d22\u5f15\u7684\u8bdd\uff0c\u6211\u4e3e\u4e2a\u4f8b\u5b50\uff0c\u521b\u5efa\u4e00\u4e2a\uff08a,b\uff09\u7684\u8054\u5408\u7d22\u5f15<\/p>\n\n\n

            \n
            \"\"<\/figure><\/div>\n\n\n

            \u53ef\u4ee5\u770b\u5230 a \u7684\u503c\u662f\u6709\u987a\u5e8f\u7684\uff0c1\uff0c1\uff0c2\uff0c2\uff0c3\uff0c3\uff0c\u800c b \u7684\u503c\u662f\u6ca1\u6709\u987a\u5e8f\u7684 1\uff0c2\uff0c1\uff0c4\uff0c1\uff0c2\u3002\u4f46\u662f\u6211\u4eec\u53c8\u53ef\u53d1\u73b0 a \u5728\u7b49\u503c\u7684\u60c5\u51b5\u4e0b\uff0cb \u503c\u53c8\u662f\u6309\u987a\u5e8f\u6392\u5217\u7684\uff0c\u4f46\u662f\u8fd9\u79cd\u987a\u5e8f\u662f\u76f8\u5bf9\u7684\u3002\u8fd9\u662f\u56e0\u4e3a MySQL \u521b\u5efa\u8054\u5408\u7d22\u5f15\u7684\u89c4\u5219\u662f\u9996\u5148\u4f1a\u5bf9\u8054\u5408\u7d22\u5f15\u7684\u6700\u5de6\u8fb9\u7b2c\u4e00\u4e2a\u5b57\u6bb5\u6392\u5e8f\uff0c\u5728\u7b2c\u4e00\u4e2a\u5b57\u6bb5\u7684\u6392\u5e8f\u57fa\u7840\u4e0a\uff0c\u7136\u540e\u5728\u5bf9\u7b2c\u4e8c\u4e2a\u5b57\u6bb5\u8fdb\u884c\u6392\u5e8f\u3002\u6240\u4ee5 b=2 \u8fd9\u79cd\u67e5\u8be2\u6761\u4ef6\u6ca1\u6709\u529e\u6cd5\u5229\u7528\u7d22\u5f15\u3002\u4e3e\u4e2a\u4f8b\u5b50\uff0c\u6211\u5f04\u4e00\u4e2a\u7d22\u5f15\uff0c<\/p>\n\n\n\n

             KEY idx_time_zone (time_zone,time_string) USING BTREE<\/pre>\n\n\n\n
            \u6267\u884c\u7b2c\u4e00\u6761 sql, \u5168\u8868\u626b\u63cf<\/p>\n\n\n
            \n
            \"\"<\/figure><\/div>\n\n\n
            \u6267\u884c\u7b2c\u4e8c\u6761 sql\uff0c\u53ef\u4ee5\u770b\u5230\u4f7f\u7528\u4e86\u7d22\u5f15\u3002<\/p>\n\n\n
            \n
            \"\"<\/figure><\/div>\n\n\n
            \u518d\u770b\u4e24\u6761 sql\uff0c\u5efa\u7acb\u7684\u7d22\u5f15\u662f KEY idx_time_zone<\/code> (time_zone<\/code>,time_string<\/code>) USING BTREE<\/p>\n\n\n
            \n
            \"\"<\/figure><\/div>\n\n\n
            \u6309\u7167\u6b63\u5e38\u903b\u8f91\u6765\u8bf4\uff0c\u7b2c\u4e8c\u6761 sql \u662f\u4e0d\u7b26\u5408\u7d22\u5f15\u5b57\u6bb5\u7684\u987a\u5e8f\u7684\uff0c\u5e94\u8be5\u4e0d\u80fd\u4f7f\u7528\u7d22\u5f15\u624d\u5bf9\uff0c\u4f46\u662f\u5b9e\u9645\u60c5\u51b5\u5374\u548c\u6211\u4eec\u671f\u671b\u7684\u4e0d\u592a\u4e00\u6837\uff0c\u8fd9\u662f\u4e3a\u5565\u5462\uff1f<\/p>\n\n\n\n
            \u4ece mysql \u88ab oracle \u6536\u8d2d\u4ee5\u540e\uff0cmysql \u52a0\u5165\u4e86\u5f88\u591a oracle \u4ee5\u524d\u7684\u6280\u672f\uff0c\u9ad8\u7248\u672c mysql \u81ea\u52a8\u4f18\u5316\u4e86 where \u6761\u4ef6\u7684\u5148\u540e\u987a\u5e8f\u3002\u7b80\u5355\u6765\u8bf4\u5c31\u662f\u67e5\u8be2\u4f18\u5316\u5668\u505a\u4e86\u8fd9\u4e00\u6b65\u64cd\u4f5c\uff0csql \u4f1a\u505a\u9884\u5904\u7406\uff0c\u90a3\u4e00\u6761\u80fd\u66f4\u597d\u7684\u67e5\u8be2\u5c31\u4f1a\u4f7f\u7528\u90a3\u79cd\u89c4\u5219\u3002<\/p>\n\n\n\n
            \u987a\u4fbf\u63d0\u4e00\u4e0b mysql \u7684\u67e5\u8be2\u4f18\u5316\u5668\u80fd\u5e2e\u5fd9\u5e72\u7684\u4e00\u4e9b\u4e8b<\/p>\n\n\n\n
            6.1 \u6761\u4ef6\u8f6c\u5316<\/strong><\/p>\n\n\n\n
            \u4f8b\u5982 where a=b and b=2\uff0c\u53ef\u4ee5\u5f97\u5230 a=2, \u6761\u4ef6\u4f20\u9012\u3002\u6700\u540e\u7684 sql \u662f a=2 and b=2 > < = like \u90fd\u53ef\u4ee5\u4f20\u9012<\/p>\n\n\n\n
            6.2 \u65e0\u6548\u4ee3\u7801\u7684\u6392\u9664<\/strong><\/p>\n\n\n\n
            \u4f8b\u5982 where 1=1 and a=2, 1=1 \u6c38\u8fdc\u662f\u6b63\u786e\u7684\uff0c\u6240\u4ee5\u6700\u540e\u4f1a\u4f18\u5316\u6210 a=2
            \u5728\u6bd4\u5982 where 1=0 \u6c38\u8fdc\u662f false \u7684\uff0c\u8fd9\u6837\u7684\u4e5f\u4f1a\u88ab\u6392\u9664\u6389\uff0c\u6574 sql \u65e0\u6548
            \u6216\u8005\u975e\u7a7a\u5b57\u6bb5 where a is null , \u8fd9\u6837\u7684\u4e5f\u4f1a\u88ab\u6392\u9664<\/p>\n\n\n\n
            6.3 \u63d0\u524d\u8ba1\u7b97<\/strong><\/p>\n\n\n\n
            \u5305\u542b\u6570\u5b66\u8fd0\u7b97\u7684\u90e8\u5206\uff0c\u4f8b\u5982 where a= 1+2 \u4f1a\u5e2e\u4f60\u7b97\u597d\uff0cwhere a=3<\/p>\n\n\n\n
            6.4 \u5b58\u53d6\u7c7b\u578b<\/strong><\/p>\n\n\n\n
            \u5f53\u6211\u4eec\u8bc4\u4f30\u4e00\u4e2a\u6761\u4ef6\u8868\u8fbe\u5f0f\uff0cMySQL \u5224\u65ad\u8be5\u8868\u8fbe\u5f0f\u7684\u5b58\u53d6\u7c7b\u578b\u3002\u4e0b\u9762\u662f\u4e00\u4e9b\u5b58\u53d6\u7c7b\u578b\uff0c\u6309\u7167\u4ece\u6700\u4f18\u5230\u6700\u5dee\u7684\u987a\u5e8f\u8fdb\u884c\u6392\u5217\uff1a<\/p>\n\n\n\n
              \n
            • system \u7cfb\u7edf\u8868\uff0c\u5e76\u4e14\u662f\u5e38\u91cf\u8868<\/li>\n\n\n\n
            • const \u5e38\u91cf\u8868<\/li>\n\n\n\n
            • eq_ref unique\/primary \u7d22\u5f15\uff0c\u5e76\u4e14\u4f7f\u7528\u7684\u662f\u2019=\u2019\u8fdb\u884c\u5b58\u53d6<\/li>\n\n\n\n
            • ref \u7d22\u5f15\u4f7f\u7528\u2019=\u2019\u8fdb\u884c\u5b58\u53d6<\/li>\n\n\n\n
            • ref_or_null \u7d22\u5f15\u4f7f\u7528\u2019=\u2019\u8fdb\u884c\u5b58\u53d6\uff0c\u5e76\u4e14\u6709\u53ef\u80fd\u4e3a NULL<\/li>\n\n\n\n
            • range \u7d22\u5f15\u4f7f\u7528 BETWEEN\u3001IN\u3001>=\u3001LIKE \u7b49\u8fdb\u884c\u5b58\u53d6<\/li>\n\n\n\n
            • index \u7d22\u5f15\u5168\u626b\u63cf<\/li>\n\n\n\n
            • ALL \u8868\u5168\u626b\u63cf<\/li>\n<\/ul>\n\n\n\n
              \u7ecf\u5e38\u770b\u6267\u884c\u8ba1\u5212\u7684\uff0c\u4e00\u773c\u5c31\u80fd\u770b\u51fa\u6765\u8fd9\u662f\u5565\u610f\u601d\uff0c\u4e3e\u4e2a\u4f8b\u5b50<\/p>\n\n\n\n
              where index_col=2 and normal_col =3 \u8fd9\u91cc\u5c31\u4f1a\u9009\u7528 index_col=2 \u4f1a\u4f5c\u4e3a\u9a71\u52a8\u9879\u3002\u9a71\u52a8\u9879\u7684\u610f\u601d\u662f\u6307\u4e00\u4e2a sql \u9009\u5b9a\u4ed6\u7684\u6267\u884c\u8ba1\u5212\u7684\u65f6\u5019\uff0c\u53ef\u80fd\u6709\u591a\u6761\u6267\u884c\u8def\u5f84\uff0c\u4e00\u4e2a\u662f\u5168\u8868\u626b\u63cf\uff0c\u518d\u8fc7\u6ee4\u662f\u5426\u7b26\u5408\u7d22\u5f15\u5b57\u6bb5\u53ca\u975e\u7d22\u5f15\u5b57\u6bb5\u7684\u503c\u3002\u53e6\u4e00\u79cd\u662f\u901a\u8fc7\u7d22\u5f15\u5b57\u6bb5\uff0c\u952e\u503c = 2 \u627e\u5230\u5bf9\u5e94\u7684\u7d22\u5f15\u6811\uff0c\u8fc7\u6ee4\u540e\u7684\u7ed3\u679c\uff0c\u518d\u6bd4\u8f83\u662f\u5426\u7b26\u5408\u975e\u7d22\u5f15\u5b57\u6bb5\u7684\u503c\u3002\u4e00\u822c\u60c5\u51b5\u4e0b\uff0c\u8d70\u7d22\u5f15\u90fd\u6bd4\u5168\u8868\u626b\u63cf\u9700\u8981\u8bfb\u53d6\u78c1\u76d8\u7684\u6b21\u6570\u5c11\uff0c\u6240\u4ee5\u79f0\u5b83\u4e3a\u66f4\u597d\u7684\u6267\u884c\u8def\u5f84\uff0c\u4e5f\u5c31\u662f\u901a\u8fc7\u7d22\u5f15\u5b57\u6bb5\uff0c\u4f5c\u4e3a\u5176\u9a71\u52a8\u8868\u8fbe\u5f0f<\/p>\n\n\n\n
              6.5 \u8303\u56f4\u5b58\u53d6<\/strong><\/p>\n\n\n\n
              \u7b80\u5355\u6765\u8bf4\uff0ca in (1,2,3) \u548c a=1 or a=2 or a=3 \u662f\u4e00\u6837\u7684\uff0cbetween 1 and 2 \u548c a>1 and a<2 \u4e5f\u662f\u4e00\u6837\u7684\uff0c \u65e0\u9700\u53ef\u4ee5\u4f18\u5316\u3002<\/p>\n\n\n\n
              6.6 \u7d22\u5f15\u5b58\u53d6\u7c7b\u578b<\/strong><\/p>\n\n\n\n
              \u907f\u514d\u4f7f\u7528\u76f8\u540c\u524d\u7f00\u7684\u7d22\u5f15\uff0c\u4e5f\u5c31\u662f\u4e00\u4e2a\u5b57\u6bb5\u4e0d\u8981\u5728\u591a\u4e2a\u7d22\u5f15\u4e0a\u6709\u76f8\u540c\u7684\u524d\u7f00\u3002\u6bd4\u5982\u4e00\u4e2a\u5b57\u6bb5\u5df2\u7ecf\u5efa\u7acb\u4e86\u552f\u4e00\u7d22\u5f15\uff0c\u8fd9\u4e2a\u65f6\u5019\u5982\u679c\u518d\u7ed9\u4ed6\u5efa\u7acb\u4e00\u4e2a\u8054\u5408\u7d22\u5f15\uff0c\u4f1a\u5bfc\u81f4\u4f18\u5316\u5668\u5e76\u4e0d\u77e5\u9053\u4f60\u8981\u4f7f\u7528\u54ea\u4e2a\u7d22\u5f15\u3002\u6216\u8005\u4f60\u5efa\u4e86\u524d\u7f00\u76f8\u540c\u7684\u4e00\u4e2a\u5355\u7d22\u5f15\uff0c\u4e00\u4e2a\u8054\u5408\u7d22\u5f15\uff0c\u5c31\u7b97\u4f60\u5199\u4e0a\u4e86\u6761\u4ef6\uff0c\u4e5f\u4e0d\u4e00\u5b9a\u80fd\u7528\u4e0a\u8054\u5408\u7d22\u5f15\u3002\u5f53\u7136\uff0c\u53ef\u4ee5 force\uff0c\u8fd9\u5c31\u53e6\u8bf4\u4e86\u3002<\/p>\n\n\n\n
              6.7 \u8f6c\u6362<\/strong><\/p>\n\n\n\n
              \u7b80\u5355\u7684\u8868\u8fbe\u5f0f\u53ef\u4ee5\u8fdb\u884c\u8f6c\u6362\uff0c\u6bd4\u5982 where -2 = a \u4f1a\u81ea\u52a8\u53d8\u6210 where a= -2 \uff0c\u4f46\u662f\u5982\u679c\u7275\u626f\u5230\u6570\u5b66\u8fd0\u7b97\uff0c\u5c31\u4e0d\u80fd\u8f6c\u6362\u4e86 \u6bd4\u5982 where 2= -a \u8fd9\u65f6\u5019\u4e0d\u4f1a\u81ea\u52a8\u8f6c\u6210 where a =-2.<\/p>\n\n\n
              \n
              \"\"<\/figure><\/div>\n\n\n
              \u7b2c\u4e8c\u6761 sql \u5c31\u53ef\u4ee5\u4f7f\u7528\u7d22\u5f15<\/p>\n\n\n
              \n
              \"\"<\/figure><\/div>\n\n\n
              \u6240\u4ee5 \u6211\u4eec\u5728\u5f00\u53d1\u7684\u8fc7\u7a0b\u4e2d\uff0c\u9700\u8981\u6ce8\u610f sql \u7684\u5199\u6cd5\uff0c\u81ea\u89c9\u5199\u6210 where a=-2<\/p>\n\n\n\n
              6.8 and\u3001union\u3001order by\u3001group by \u7b49<\/strong><\/p>\n\n\n\n
              1\uff09and<\/p>\n\n\n\n
              and \u6761\u4ef6\u540e\uff0c\u5982\u679c\u90fd\u6ca1\u7d22\u5f15\uff0c\u626b\u63cf\u5168\u8868\u3002<\/p>\n\n\n\n
              2\uff09union<\/p>\n\n\n\n
              union \u6bcf\u6761\u8bed\u53e5\u5355\u72ec\u4f18\u5316<\/p>\n\n\n
              \n
              \"\"<\/figure><\/div>\n\n\n
              \u8fd9\u91cc\u5c31\u4f1a\u5206\u522b\u6267\u884c\u4e24\u6761 sql\uff0c\u7528\u5230\u7d22\u5f15\uff0c\u518d\u5408\u5e76\u7ed3\u679c\u96c6<\/p>\n\n\n\n
              3\uff09order by<\/p>\n\n\n\n
              order by \u4f1a\u8fc7\u6ee4\u65e0\u6548\u6392\u5e8f\uff0c\u6bd4\u5982\u4e00\u4e2a\u5b57\u6bb5\u672c\u6765\u5c31\u6709\u7d22\u5f15<\/p>\n\n\n
              \n
              \"\"<\/figure><\/div>\n\n\n
              \u7b2c\u4e8c\u6761 sql \u548c\u7b2c\u4e00\u6761\u7684\u67e5\u8be2\u6548\u679c\u662f\u4e00\u6837\u7684<\/p>\n\n\n
              \n
              \"\"<\/figure><\/div>\n\n\n
              \u6240\u4ee5\uff0c\u5199 sql \u7684\u65f6\u5019\uff0c\u4e0d\u8981\u5199\u65e0\u7528\u6392\u5e8f\uff0c\u6bd4\u5982 order by \u2018xxx\u2019 \u8fd9\u6837\u6ca1\u6709\u610f\u4e49\u3002<\/p>\n\n\n\n
              4\uff09group by<\/p>\n\n\n\n
              \u7b80\u5355\u6765\u8bf4 group by \u7684\u5b57\u6bb5\uff0c\u6709\u7d22\u5f15\u4f1a\u8d70\u7d22\u5f15\uff0cgroup by a order by a \u8fd9\u91cc\u7684 order by \u7b49\u4e8e\u6ca1\u5199\uff0c\u7ed3\u679c\u96c6\u5df2\u7ecf\u662f\u6392\u5e8f\u5b8c\u6bd5\u7684\u4e86\uff0c\u53c2\u8003 6.8-3 order by
              select distinct col_a from table a \u7b49\u4ef7\u4e8e select col_a from a group by col_a<\/p>\n\n\n\n
              7.\u7d22\u5f15\u4e0b\u63a8<\/strong><\/p>\n\n\n\n
              \n\n\n\n
              \u4e3b\u8981\u7684\u6838\u5fc3\u70b9\u5c31\u5728\u4e8e\u628a\u6570\u636e\u7b5b\u9009\u7684\u8fc7\u7a0b\u653e\u5728\u4e86\u5b58\u50a8\u5f15\u64ce\u5c42\u53bb\u5904\u7406\uff0c\u800c\u4e0d\u662f\u50cf\u4e4b\u524d\u4e00\u6837\u653e\u5230 Server \u5c42\u53bb\u505a\u8fc7\u6ee4\u3002<\/p>\n\n\n\n
              \u5982\u679c\u5728\u4e00\u5f20\u8868\u4e0a\uff0cname \u548c age \u90fd\u5efa\u7acb\u7d22\u5f15\uff0c\u67e5\u8be2\u6761\u4ef6\u4e3a where name like \u2018xx%\u2019 and age=11, \u5728\u4f4e\u7248\u672c\u7684 mysql (5.6 \u4ee5\u4e0b) \u7684\u6839\u636e\u7d22\u5f15\u7684\u6700\u5de6\u5339\u914d\u539f\u5219\uff0c\u53ef\u4ee5\u5f97\u5230\u653e\u5f03\u4e86 age\uff0c\u53ea\u6839\u636e name \u8fc7\u6ee4\u6570\u636e\u3002\u6839\u636e name \u62ff\u5230\u6240\u6709\u7684 id \u4e4b\u540e\uff0c\u518d\u6839\u636e id \u56de\u8868\u3002<\/p>\n\n\n\n
              \u9ad8\u7248\u672c mysql \u91cc\uff0c\u6ca1\u6709\u5ffd\u7565 age \u8fd9\u4e2a\u5c5e\u6027\uff0c\u5e26\u7740 age \u5c5e\u6027\u8fc7\u6ee4\uff0c\u76f4\u63a5\u8fc7\u6ee4\u6389\u4e86 age \u4e3a 11 \u7684\u6570\u636e\uff0c\u5047\u8bbe\u4e0d\u6839\u636e age \u8fc7\u6ee4\u7684\u6570\u636e\u4e3a 10 \u6761\uff0c\u8fc7\u6ee4\u540e\u53ea\u5269 3 \u6761\uff0c\u5c31\u5c11\u4e86 7 \u6b21\u56de\u8868\u3002\u51cf\u5c11\u4e86 io \u4f1a\u5927\u91cf\u51cf\u5c11\u6027\u80fd\u6d88\u8017<\/p>\n\n\n\n
              8.\u5c0f\u8868\u9a71\u52a8\u5927\u8868<\/strong><\/p>\n\n\n\n
              \n\n\n\n
              \u5c0f\u8868\u9a71\u52a8\u5927\u8868\uff0c\u4e5f\u662f\u6211\u4eec\u542c\u60ef\u4e86\u7684\u8bdd\u4e86\uff0c\u5176\u542b\u4e49\u4e3b\u8981\u662f\u6307\u5c0f\u8868\u7684\u6570\u636e\u96c6\u9a71\u52a8\u5927\u8868\u7684\u6570\u636e\u96c6\uff0c\u51cf\u5c11\u8fde\u63a5\u6b21\u6570\u3002\u6253\u4e2a\u6bd4\u65b9:<\/p>\n\n\n\n
              \u8868 A \u6709 1w \u6570\u636e\uff0c\u8868 B \u6709 100w \u6570\u636e\uff0c\u5982\u679c A \u8868\u4f5c\u4e3a\u9a71\u52a8\u8868\uff0c\u5904\u4e8e\u5faa\u73af\u7684\u5916\u5c42\uff0c\u90a3\u4e48\u53ea\u9700\u8981 1w \u6b21\u7684\u8fde\u63a5\u5373\u53ef\u3002\u5982\u679c B \u8868\u5728\u5916\u5c42\uff0c\u90a3\u4e48\u5219\u9700\u8981\u5faa\u73af 100w \u6b21\u3002<\/p>\n\n\n\n
              \u4e0b\u9762\u6211\u4eec\u5b9e\u9645\u6d4b\u8bd5\u770b\u770b\uff0c\u51c6\u5907\u73af\u5883 mysql 5.7+<\/p>\n\n\n
              \n
              \"\"<\/figure><\/div>\n\n\n
              \u51c6\u5907\u4e24\u5f20\u8868\uff0c\u4e00\u5f20\u8868 ib_asn_d \u6570\u636e 9175\uff0c \u4e00\u5f20\u8868 bs_itembase_ext_attr \u6570\u636e 1584115\uff0c\u90fd\u5728\u5546\u54c1\u7f16\u7801\u5b57\u6bb5\u4e0a\u6709\u7d22\u5f15\u3002<\/p>\n\n\n\n
              \u9996\u5148\u5c0f\u8868\u9a71\u52a8\u5927\u8868<\/p>\n\n\n
              \n
              \"\"<\/figure><\/div>\n\n\n
              \u591a\u6b21\u53cd\u590d\u6d4b\u8bd5\uff0c\u6267\u884c\u65f6\u95f4\u5927\u6982 7 \u79d2\u3002
              \u63a5\u4e0b\u6765\u770b\u770b\u5927\u8868\u9a71\u52a8\u5c0f\u8868\u3002<\/p>\n\n\n
              \n
              \"\"<\/figure><\/div>\n\n\n
              \u5c06\u8fd1 300 \u79d2\uff0c\u4e0d\u662f\u4e00\u4e2a\u91cf\u7ea7\u7684\u3002
              \u63a5\u4e0b\u6765\u5206\u522b\u5206\u6790\u6267\u884c\u8ba1\u5212\uff0c\u6267\u884c\u8ba1\u5212\u91cc\u7b2c\u4e00\u6761\u5c31\u662f\u9a71\u52a8\u8868\u3002<\/p>\n\n\n
              \n
              \"\"<\/figure><\/div>\n\n\n
              \u5c0f\u8868\u9a71\u52a8\u5927\u8868\uff0c\u5927\u8868\u7528\u4e86\u7d22\u5f15\uff0c\u5c0f\u8868\u5168\u8868\u626b\u63cf\uff0c\u53ea\u626b\u63cf 8000 \u591a\u884c<\/p>\n\n\n
              \n
              \"\"<\/figure><\/div>\n\n\n
              \u5927\u8868\u9a71\u52a8\u5c0f\u8868\uff0c\u5927\u8868\u5168\u8868\u626b\u63cf\uff0c\u9700\u8981\u626b\u63cf 147w \u884c\u3002
              \u7ecf\u8fc7\u591a\u6b21\u6d4b\u8bd5\u5f97\u51fa\u4e86\u7ed3\u8bba:<\/p>\n\n\n\n
                \n
              1. \u5f53\u4f7f\u7528 left join \u65f6\uff0c\u5de6\u8868\u662f\u9a71\u52a8\u8868\uff0c\u53f3\u8868\u662f\u88ab\u9a71\u52a8\u8868\uff1b<\/li>\n\n\n\n
              2. \u5f53\u4f7f\u7528 right join \u65f6\uff0c\u53f3\u8868\u662f\u9a71\u52a8\u8868\uff0c\u5de6\u8868\u662f\u88ab\u9a71\u52a8\u8868\uff1b<\/li>\n\n\n\n
              3. \u5f53\u4f7f\u7528 inner join \u65f6\uff0cmysql \u4f1a\u9009\u62e9\u6570\u636e\u91cf\u6bd4\u8f83\u5c0f\u7684\u8868\u4f5c\u4e3a\u9a71\u52a8\u8868\uff0c\u5927\u8868\u4f5c\u4e3a\u88ab\u9a71\u52a8\u8868\uff1b<\/li>\n\n\n\n
              4. \u9a71\u52a8\u8868\u7d22\u5f15\u4e0d\u751f\u6548\uff0c\u975e\u9a71\u52a8\u8868\u7d22\u5f15\u751f\u6548<\/li>\n<\/ol>\n\n\n\n
                \u4fdd\u8bc1\u5c0f\u8868\u662f\u9a71\u52a8\u8868\u5f88\u91cd\u8981\u3002<\/p>\n\n\n\n
                9.\u6570\u636e\u5e93\u7d22\u5f15\u6709\u54ea\u4e9b\u5462<\/strong><\/p>\n\n\n\n
                \n\n\n\n
                  \n
                1. \u805a\u96c6\u7d22\u5f15\uff08\u4e3b\u952e\u7d22\u5f15\uff09\uff1a\u5728\u6570\u636e\u5e93\u91cc\u9762\uff0c\u6240\u6709\u884c\u6570\u90fd\u4f1a\u6309\u7167\u4e3b\u952e\u7d22\u5f15\u8fdb\u884c\u6392\u5e8f\u3002<\/li>\n\n\n\n
                2. \u975e\u805a\u96c6\u7d22\u5f15\uff1a\u5c31\u662f\u7ed9\u666e\u901a\u5b57\u6bb5\u52a0\u4e0a\u7d22\u5f15\u3002<\/li>\n\n\n\n
                3. \u8054\u5408\u7d22\u5f15\uff1a\u5c31\u662f\u597d\u51e0\u4e2a\u5b57\u6bb5\u7ec4\u6210\u7684\u7d22\u5f15\uff0c\u79f0\u4e3a\u8054\u5408\u7d22\u5f15\u3002<\/li>\n<\/ol>\n\n\n\n
                  \nkey 'idx_age_name_sex' ('age','name','sex')\n<\/pre>\n\n\n\n
                  MySQL\u8054\u5408\u7d22\u5f15\u751f\u6548\u7684\u539f\u5219\u662f\u9075\u5faa\u6700\u5de6\u524d\u7f00\u539f\u5219\u3002\u4e5f\u5c31\u662f\u8bf4\uff0c\u8054\u5408\u7d22\u5f15\u5728\u67e5\u8be2\u65f6\uff0c\u53ea\u6709\u6309\u7167\u7d22\u5f15\u7684\u6700\u5de6\u8fb9\u7684\u5217\u5f00\u59cb\u67e5\u8be2\u65f6\uff0c\u7d22\u5f15\u624d\u4f1a\u751f\u6548\u3002\u5982\u679c\u4e0d\u6309\u7167\u6700\u5de6\u8fb9\u7684\u5217\u5f00\u59cb\u67e5\u8be2\uff0c\u90a3\u4e48\u7d22\u5f15\u5c06\u4e0d\u4f1a\u88ab\u4f7f\u7528\u3002<\/p>\n\n\n\n
                  \u4f8b\u5982\uff0c\u5bf9\u4e8e\u4e00\u4e2a\u8054\u5408\u7d22\u5f15 (col1, col2, col3)\uff0c\u5f53\u67e5\u8be2\u6761\u4ef6\u4e2d\u5305\u542b col1 \u548c col2 \u65f6\uff0c\u7d22\u5f15\u4f1a\u88ab\u4f7f\u7528\uff1b\u5f53\u53ea\u5305\u542b col2 \u6216\u53ea\u5305\u542b col3 \u65f6\uff0c\u7d22\u5f15\u4e0d\u4f1a\u88ab\u4f7f\u7528\u3002<\/p>\n\n\n\n
                  \u6b64\u5916\uff0c\u8054\u5408\u7d22\u5f15\u7684\u987a\u5e8f\u4e5f\u5f88\u91cd\u8981\u3002\u5bf9\u4e8e\u4e00\u4e2a\u8054\u5408\u7d22\u5f15 (col1, col2, col3)\uff0c\u5982\u679c\u67e5\u8be2\u6761\u4ef6\u53ea\u5305\u542b col2 \u548c col3\uff0c\u800c\u4e0d\u5305\u542b col1\uff0c\u7d22\u5f15\u4e5f\u4e0d\u4f1a\u88ab\u4f7f\u7528\uff0c\u56e0\u4e3a\u67e5\u8be2\u6761\u4ef6\u6ca1\u6709\u6309\u7167\u7d22\u5f15\u7684\u987a\u5e8f\u6765\u5339\u914d\u3002\u56e0\u6b64\uff0c\u5728\u521b\u5efa\u8054\u5408\u7d22\u5f15\u65f6\uff0c\u9700\u8981\u6839\u636e\u5b9e\u9645\u67e5\u8be2\u7684\u60c5\u51b5\u6765\u786e\u5b9a\u7d22\u5f15\u7684\u987a\u5e8f\u3002<\/p>\n\n\n\n
                  \u5c31\u6bd4\u5982\u8bf4\u4e00\u5f20\u5b66\u751f\u8868\u91cc\u9762\u7684\u8054\u5408\u7d22\u5f15\u5982\u4e0a\u9762\u6240\u793a\uff0c\u90a3\u4e48\u4e0b\u9762A,B,C,D,E,F\u54ea\u4e2a\u4f1a\u8d70\u7d22\u5f15\u5462\uff1f<\/p>\n\n\n\n
                  A:select * from student where age = 16 and name = '\u5c0f\u5f20'\nB:select * from student where name = '\u5c0f\u5f20' and sex = '\u7537'\nC:select * from student where name = '\u5c0f\u5f20' and sex = '\u7537' and age = 18\nD:select * from student where age > 20 and name = '\u5c0f\u5f20'\nE:select * from student where age != 15 and name = '\u5c0f\u5f20'\nF:select * from student where age = 1<\/pre>\n\n\n\n
                   A\u9075\u4ece\u6700\u5de6\u5339\u914d\u539f\u5219\uff0cage\u662f\u5728\u6700\u5de6\u8fb9\uff0c\u6240\u4ee5A\u8d70\u7d22\u5f15\uff1b\n\n B\u76f4\u63a5\u4ecename\u5f00\u59cb\uff0c\u6ca1\u6709\u9075\u4ece\u6700\u5de6\u5339\u914d\u539f\u5219\uff0c\u6240\u4ee5\u4e0d\u8d70\u7d22\u5f15\uff1b\n\n C\u867d\u7136\u4ecename\u5f00\u59cb\uff0c\u4f46\u662f\u6709\u7d22\u5f15\u6700\u5de6\u8fb9\u7684age\uff0cmysql\u5185\u90e8\u4f1a\u81ea\u52a8\u8f6c\u6210where age = '18' and name = '\u5c0f\u5f20'  and sex = '\u7537' \u8fd9\u79cd\uff0c\u6240\u4ee5\u8fd8\u662f\u9075\u4ece\u6700\u5de6\u5339\u914d\u539f\u5219\uff1b\n\n D\u8fd9\u4e2a\u662f\u56e0\u4e3aage>20\u662f\u8303\u56f4\uff0c\u8303\u56f4\u5b57\u6bb5\u4f1a\u7ed3\u675f\u7d22\u5f15\u5bf9\u8303\u56f4\u540e\u9762\u7d22\u5f15\u5b57\u6bb5\u7684\u4f7f\u7528\uff0c\u6240\u4ee5\u53ea\u6709\u8d70\u4e86age\u8fd9\u4e2a\u7d22\u5f15\uff1b\n\n E\u8fd9\u4e2a\u867d\u7136\u9075\u5faa\u6700\u5de6\u5339\u914d\u539f\u5219\uff0c\u4f46\u662f\u4e0d\u8d70\u7d22\u5f15\uff0c\u56e0\u4e3a!= \u4e0d\u8d70\u7d22\u5f15\uff1b\n\n F\u8fd9\u4e2a\u53ea\u8d70age\u7d22\u5f15\uff0c\u4e0d\u8d70name\u7d22\u5f15\uff0c\u539f\u56e0\u5982\u4e0a\uff1b<\/pre>\n\n\n\n
                  10.\u6709\u54ea\u4e9b\u5217\u5b50\u4e0d\u8d70\u7d22\u5f15\u5462<\/strong><\/p>\n\n\n\n
                  \n\n\n\n
                  \u8868student\u4e2d\u4e24\u4e2a\u5b57\u6bb5age,name\u52a0\u4e86\u7d22\u5f15<\/p>\n\n\n\n
                  \nkey 'idx_age' ('age'),\nkey 'idx_name' ('name')\n<\/pre>\n\n\n\n
                  10.1 <\/strong>\u00a0Like\u8fd9\u79cd\u5c31\u662f%\u5728\u524d\u9762\u7684\u4e0d\u8d70\u7d22\u5f15\uff0c\u5728\u540e\u9762\u7684\u8d70\u7d22\u5f15<\/p>\n\n\n\n
                  \nA:select * from student where 'name' like '\u738b%'\nB:select * from student where 'name' like '%\u5c0f'\nA\u8d70\u7d22\u5f15\uff0cB\u4e0d\u8d70\u7d22\u5f15<\/pre>\n\n\n\n
                  10.2<\/strong> \u7528\u7d22\u5f15\u5217\u8fdb\u884c\u8ba1\u7b97\u7684\uff0c\u4e0d\u8d70\u7d22\u5f15<\/p>\n\n\n\n
                  \nA:select * from student where age = 10+8\nB:select * from student where age + 8 = 18\nA\u8d70\u7d22\u5f15\uff0cB\u4e0d\u8d70\u7d22\u5f15<\/pre>\n\n\n\n
                  10.3<\/strong> \u5bf9\u7d22\u5f15\u5217\u7528\u51fd\u6570\u4e86\uff0c\u4e0d\u8d70\u7d22\u5f15<\/p>\n\n\n\n
                  \nA:select * from student where  concat('name','\u54c8') ='\u738b\u54c8\u54c8';\nB:select * from student where name = concat('\u738b\u54c8','\u54c8');\nA\u4e0d\u8d70\u7d22\u5f15\uff0cB\u8d70\u7d22\u5f15<\/pre>\n\n\n\n
                  10.4<\/strong> \u7d22\u5f15\u5217\u7528\u4e86!= \u4e0d\u8d70\u7d22\u5f15,\u5982\u4e0b\uff1a<\/p>\n\n\n\n
                  \nselect * from student where age != 18\n<\/pre>\n\n\n\n
                  11.\u603b\u7ed3<\/strong><\/p>\n\n\n\n
                  \n\n\n\n
                    \n
                  • \u8986\u76d6\u7d22\u5f15\uff1a\u5982\u679c\u67e5\u8be2\u6761\u4ef6\u4f7f\u7528\u7684\u662f\u666e\u901a\u7d22\u5f15\uff08\u6216\u662f\u8054\u5408\u7d22\u5f15\u7684\u6700\u5de6\u539f\u5219\u5b57\u6bb5\uff09\uff0c\u67e5\u8be2\u7ed3\u679c\u662f\u8054\u5408\u7d22\u5f15\u7684\u5b57\u6bb5\u6216\u662f\u4e3b\u952e\uff0c\u4e0d\u7528\u56de\u8868\u64cd\u4f5c\uff0c\u76f4\u63a5\u8fd4\u56de\u7ed3\u679c\uff0c\u51cf\u5c11 IO \u78c1\u76d8\u8bfb\u5199\u8bfb\u53d6\u6574\u884c\u6570\u636e\uff0c\u6240\u4ee5\u9ad8\u9891\u5b57\u6bb5\u5efa\u7acb\u8054\u5408\u7d22\u5f15\u662f\u5f88\u6709\u5fc5\u8981\u7684<\/li>\n\n\n\n
                  • \u6700\u5de6\u524d\u7f00\uff1a\u8054\u5408\u7d22\u5f15\u7684\u6700\u5de6 N \u4e2a\u5b57\u6bb5\uff0c\u4e5f\u53ef\u4ee5\u662f\u5b57\u7b26\u4e32\u7d22\u5f15\u7684\u6700\u5de6 M \u4e2a\u5b57\u7b26\u3002\u5efa\u7acb\u7d22\u5f15\u7684\u65f6\u5019\uff0c\u6ce8\u610f\u5de6\u524d\u7f00\u4e0d\u8981\u91cd\u590d\uff0c\u907f\u514d\u67e5\u8be2\u4f18\u5316\u5668\u65e0\u6cd5\u5224\u5b9a\u5982\u4f55\u4f7f\u7528\u7d22\u5f15<\/li>\n\n\n\n
                  • \u7d22\u5f15\u4e0b\u63a8\uff1aname like \u2018hello%\u2019and age >10 \u68c0\u7d22\uff0cMySQL 5.6 \u7248\u672c\u4e4b\u524d\uff0c\u4f1a\u5bf9\u5339\u914d\u7684\u6570\u636e\u8fdb\u884c\u56de\u8868\u67e5\u8be2\u30025.6 \u7248\u672c\u540e\uff0c\u4f1a\u5148\u8fc7\u6ee4\u6389 age<10 \u7684\u6570\u636e\uff0c\u518d\u8fdb\u884c\u56de\u8868\u67e5\u8be2\uff0c\u51cf\u5c11\u56de\u8868\u7387\uff0c\u63d0\u5347\u68c0\u7d22\u901f\u5ea6<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"
                    \u8f6c\u8f7d\uff1ahttps:\/\/my.oschina.net\/u\/4090830\/blog\/10320986 \u4f5c\u4e3a\u5f00\u53d1\u4eba […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[23],"tags":[],"_links":{"self":[{"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/posts\/16298"}],"collection":[{"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/92it.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=16298"}],"version-history":[{"count":4,"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/posts\/16298\/revisions"}],"predecessor-version":[{"id":16327,"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/posts\/16298\/revisions\/16327"}],"wp:attachment":[{"href":"https:\/\/92it.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=16298"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/92it.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=16298"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/92it.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=16298"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}