{"id":13672,"date":"2024-02-20T13:31:10","date_gmt":"2024-02-20T05:31:10","guid":{"rendered":"https:\/\/92it.top\/?p=13672"},"modified":"2024-02-20T13:31:10","modified_gmt":"2024-02-20T05:31:10","slug":"8%e7%a7%8d%e4%b8%93%e5%9d%91%e5%90%8c%e4%ba%8b%e7%9a%84-sql-%e5%86%99%e6%b3%95%ef%bc%8c%e6%80%a7%e8%83%bd%e9%99%8d%e4%bd%8e100%e5%80%8d%ef%bc%8c%e4%b8%8d%e6%9d%a5%e7%9c%8b%e7%9c%8b%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/92it.top\/?p=13672","title":{"rendered":"8\u79cd\u4e13\u5751\u540c\u4e8b\u7684 SQL \u5199\u6cd5\uff0c\u6027\u80fd\u964d\u4f4e100\u500d\uff0c\u4e0d\u6765\u770b\u770b\uff1f"},"content":{"rendered":"\n

sql\u8bed\u53e5\u7684\u6267\u884c\u987a\u5e8f<\/strong><\/p>\n\n\n\n

\"\"<\/figure><\/div>\n\n\n\n
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FROM\n<left_table>\n\nON\n<join_condition>\n\n<join_type>\n JOIN\n<right_table>\n\nWHERE\n<where_condition>\n\nGROUP BY\n<group_by_list>\n\nHAVING\n<having_condition>\n\nSELECT\n\nDISTINCT\n<select_list>\n\nORDER BY\n<order_by_condition>\n\nLIMIT\n<limit_number><\/pre>\n\n\n\n
1\u3001LIMIT \u8bed\u53e5<\/strong><\/p>\n\n\n\n
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\u5206\u9875\u67e5\u8be2\u662f\u6700\u5e38\u7528\u7684\u573a\u666f\u4e4b\u4e00\uff0c\u4f46\u4e5f\u901a\u5e38\u4e5f\u662f\u6700\u5bb9\u6613\u51fa\u95ee\u9898\u7684\u5730\u65b9\u3002\u6bd4\u5982\u5bf9\u4e8e\u4e0b\u9762\u7b80\u5355\u7684\u8bed\u53e5\uff0c\u4e00\u822c DBA \u60f3\u5230\u7684\u529e\u6cd5\u662f\u5728 type, name, create_time \u5b57\u6bb5\u4e0a\u52a0\u7ec4\u5408\u7d22\u5f15\u3002\u8fd9\u6837\u6761\u4ef6\u6392\u5e8f\u90fd\u80fd\u6709\u6548\u7684\u5229\u7528\u5230\u7d22\u5f15\uff0c\u6027\u80fd\u8fc5\u901f\u63d0\u5347\u3002<\/p>\n\n\n\n
SELECT *\nFROM   operation\nWHERE  type = 'SQLStats'\n       AND name = 'SlowLog'\nORDER  BY create_time\nLIMIT  1000, 10;<\/pre>\n\n\n\n
\u597d\u5427\uff0c\u53ef\u80fd90%\u4ee5\u4e0a\u7684 DBA \u89e3\u51b3\u8be5\u95ee\u9898\u5c31\u5230\u6b64\u4e3a\u6b62\u3002\u4f46\u5f53 LIMIT \u5b50\u53e5\u53d8\u6210 \u201cLIMIT 1000000,10\u201d \u65f6\uff0c\u7a0b\u5e8f\u5458\u4ecd\u7136\u4f1a\u62b1\u6028\uff1a\u6211\u53ea\u53d610\u6761\u8bb0\u5f55\u4e3a\u4ec0\u4e48\u8fd8\u662f\u6162\uff1f<\/p>\n\n\n\n
\u8981\u77e5\u9053\u6570\u636e\u5e93\u4e5f\u5e76\u4e0d\u77e5\u9053\u7b2c1000000\u6761\u8bb0\u5f55\u4ece\u4ec0\u4e48\u5730\u65b9\u5f00\u59cb\uff0c\u5373\u4f7f\u6709\u7d22\u5f15\u4e5f\u9700\u8981\u4ece\u5934\u8ba1\u7b97\u4e00\u6b21\u3002\u51fa\u73b0\u8fd9\u79cd\u6027\u80fd\u95ee\u9898\uff0c\u591a\u6570\u60c5\u5f62\u4e0b\u662f\u7a0b\u5e8f\u5458\u5077\u61d2\u4e86\u3002<\/p>\n\n\n\n
\u5728\u524d\u7aef\u6570\u636e\u6d4f\u89c8\u7ffb\u9875\uff0c\u6216\u8005\u5927\u6570\u636e\u5206\u6279\u5bfc\u51fa\u7b49\u573a\u666f\u4e0b\uff0c\u662f\u53ef\u4ee5\u5c06\u4e0a\u4e00\u9875\u7684\u6700\u5927\u503c\u5f53\u6210\u53c2\u6570\u4f5c\u4e3a\u67e5\u8be2\u6761\u4ef6\u7684\u3002SQL \u91cd\u65b0\u8bbe\u8ba1\u5982\u4e0b\uff1a<\/p>\n\n\n\n
SELECT   *\nFROM     operation\nWHERE    type = 'SQLStats'\nAND      name = 'SlowLog'\nAND      create_time > '2017-03-16 14:00:00'\nORDER BY create_time limit 10;<\/pre>\n\n\n\n
\u5728\u65b0\u8bbe\u8ba1\u4e0b\u67e5\u8be2\u65f6\u95f4\u57fa\u672c\u56fa\u5b9a\uff0c\u4e0d\u4f1a\u968f\u7740\u6570\u636e\u91cf\u7684\u589e\u957f\u800c\u53d1\u751f\u53d8\u5316\u3002<\/p>\n\n\n\n
2\u3001\u9690\u5f0f\u8f6c\u6362<\/strong><\/p>\n\n\n\n
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SQL\u8bed\u53e5\u4e2d\u67e5\u8be2\u53d8\u91cf\u548c\u5b57\u6bb5\u5b9a\u4e49\u7c7b\u578b\u4e0d\u5339\u914d\u662f\u53e6\u4e00\u4e2a\u5e38\u89c1\u7684\u9519\u8bef\u3002\u6bd4\u5982\u4e0b\u9762\u7684\u8bed\u53e5\uff1a<\/p>\n\n\n\n
mysql> explain extended SELECT *\n     > FROM   my_balance b\n     > WHERE  b.bpn = 14000000123\n     >       AND b.isverified IS NULL ;\nmysql> show warnings;\n| Warning | 1739 | Cannot use ref access on index 'bpn' due to type or collation conversion on field 'bpn'<\/pre>\n\n\n\n
\u5176\u4e2d\u5b57\u6bb5 bpn \u7684\u5b9a\u4e49\u4e3a varchar(20)\uff0cMySQL \u7684\u7b56\u7565\u662f\u5c06\u5b57\u7b26\u4e32\u8f6c\u6362\u4e3a\u6570\u5b57\u4e4b\u540e\u518d\u6bd4\u8f83\u3002\u51fd\u6570\u4f5c\u7528\u4e8e\u8868\u5b57\u6bb5\uff0c\u7d22\u5f15\u5931\u6548\u3002<\/p>\n\n\n\n
\u4e0a\u8ff0\u60c5\u51b5\u53ef\u80fd\u662f\u5e94\u7528\u7a0b\u5e8f\u6846\u67b6\u81ea\u52a8\u586b\u5165\u7684\u53c2\u6570\uff0c\u800c\u4e0d\u662f\u7a0b\u5e8f\u5458\u7684\u539f\u610f\u3002\u73b0\u5728\u5e94\u7528\u6846\u67b6\u5f88\u591a\u5f88\u7e41\u6742\uff0c\u4f7f\u7528\u65b9\u4fbf\u7684\u540c\u65f6\u4e5f\u5c0f\u5fc3\u5b83\u53ef\u80fd\u7ed9\u81ea\u5df1\u6316\u5751\u3002<\/p>\n\n\n\n
3\u3001\u5173\u8054\u66f4\u65b0\u3001\u5220\u9664<\/strong><\/p>\n\n\n\n
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\u867d\u7136 MySQL5.6 \u5f15\u5165\u4e86\u7269\u5316\u7279\u6027\uff0c\u4f46\u9700\u8981\u7279\u522b\u6ce8\u610f\u5b83\u76ee\u524d\u4ec5\u4ec5\u9488\u5bf9\u67e5\u8be2\u8bed\u53e5\u7684\u4f18\u5316\u3002\u5bf9\u4e8e\u66f4\u65b0\u6216\u5220\u9664\u9700\u8981\u624b\u5de5\u91cd\u5199\u6210 JOIN\u3002<\/p>\n\n\n\n
\u6bd4\u5982\u4e0b\u9762 UPDATE \u8bed\u53e5\uff0cMySQL \u5b9e\u9645\u6267\u884c\u7684\u662f\u5faa\u73af\/\u5d4c\u5957\u5b50\u67e5\u8be2\uff08DEPENDENT SUBQUERY)\uff0c\u5176\u6267\u884c\u65f6\u95f4\u53ef\u60f3\u800c\u77e5\u3002<\/p>\n\n\n\n
UPDATE operation o\nSET    status = 'applying'\nWHERE  o.id IN (SELECT id\n                FROM   (SELECT o.id,\n                               o.status\n                        FROM   operation o\n                        WHERE  o.group = 123\n                               AND o.status NOT IN ( 'done' )\n                        ORDER  BY o.parent,\n                                  o.id\n                        LIMIT  1) t);<\/pre>\n\n\n\n
\u6267\u884c\u8ba1\u5212\uff1a<\/p>\n\n\n\n
+----+--------------------+-------+-------+---------------+---------+---------+-------+------+-----------------------------------------------------+\n| id | select_type        | table | type  | possible_keys | key     | key_len | ref   | rows | Extra                                               |\n+----+--------------------+-------+-------+---------------+---------+---------+-------+------+-----------------------------------------------------+\n| 1  | PRIMARY            | o     | index |               | PRIMARY | 8       |       | 24   | Using where; Using temporary                        |\n| 2  | DEPENDENT SUBQUERY |       |       |               |         |         |       |      | Impossible WHERE noticed after reading const tables |\n| 3  | DERIVED            | o     | ref   | idx_2,idx_5   | idx_5   | 8       | const | 1    | Using where; Using filesort                         |\n+----+--------------------+-------+-------+---------------+---------+---------+-------+------+-----------------------------------------------------+<\/pre>\n\n\n\n
\u91cd\u5199\u4e3a JOIN \u4e4b\u540e\uff0c\u5b50\u67e5\u8be2\u7684\u9009\u62e9\u6a21\u5f0f\u4ece DEPENDENT SUBQUERY \u53d8\u6210 DERIVED\uff0c\u6267\u884c\u901f\u5ea6\u5927\u5927\u52a0\u5feb\uff0c\u4ece7\u79d2\u964d\u4f4e\u52302\u6beb\u79d2\u3002<\/p>\n\n\n\n
UPDATE operation o\n       JOIN  (SELECT o.id,\n                            o.status\n                     FROM   operation o\n                     WHERE  o.group = 123\n                            AND o.status NOT IN ( 'done' )\n                     ORDER  BY o.parent,\n                               o.id\n                     LIMIT  1) t\n         ON o.id = t.id\nSET    status = 'applying'<\/pre>\n\n\n\n
\u6267\u884c\u8ba1\u5212\u7b80\u5316\u4e3a\uff1a<\/p>\n\n\n\n
+----+-------------+-------+------+---------------+-------+---------+-------+------+-----------------------------------------------------+\n| id | select_type | table | type | possible_keys | key   | key_len | ref   | rows | Extra                                               |\n+----+-------------+-------+------+---------------+-------+---------+-------+------+-----------------------------------------------------+\n| 1  | PRIMARY     |       |      |               |       |         |       |      | Impossible WHERE noticed after reading const tables |\n| 2  | DERIVED     | o     | ref  | idx_2,idx_5   | idx_5 | 8       | const | 1    | Using where; Using filesort                         |\n+----+-------------+-------+------+---------------+-------+---------+-------+------+-----------------------------------------------------+<\/pre>\n\n\n\n
4\u3001\u6df7\u5408\u6392\u5e8f<\/strong><\/p>\n\n\n\n
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MySQL \u4e0d\u80fd\u5229\u7528\u7d22\u5f15\u8fdb\u884c\u6df7\u5408\u6392\u5e8f\u3002\u4f46\u5728\u67d0\u4e9b\u573a\u666f\uff0c\u8fd8\u662f\u6709\u673a\u4f1a\u4f7f\u7528\u7279\u6b8a\u65b9\u6cd5\u63d0\u5347\u6027\u80fd\u7684\u3002<\/p>\n\n\n\n
SELECT *\nFROM   my_order o\n       INNER JOIN my_appraise a ON a.orderid = o.id\nORDER  BY a.is_reply ASC,\n          a.appraise_time DESC\nLIMIT  0, 20\n<\/pre>\n\n\n\n
\u6267\u884c\u8ba1\u5212\u663e\u793a\u4e3a\u5168\u8868\u626b\u63cf\uff1a<\/p>\n\n\n\n
+----+-------------+-------+--------+-------------+---------+---------+---------------+---------+-+\n| id | select_type | table | type   | possible_keys     | key     | key_len | ref      | rows    | Extra\n+----+-------------+-------+--------+-------------+---------+---------+---------------+---------+-+\n|  1 | SIMPLE      | a     | ALL    | idx_orderid | NULL    | NULL    | NULL    | 1967647 | Using filesort |\n|  1 | SIMPLE      | o     | eq_ref | PRIMARY     | PRIMARY | 122     | a.orderid |       1 | NULL           |\n+----+-------------+-------+--------+---------+---------+---------+-----------------+---------+-+\n<\/pre>\n\n\n\n
\u7531\u4e8e is_reply \u53ea\u67090\u548c1\u4e24\u79cd\u72b6\u6001\uff0c\u6211\u4eec\u6309\u7167\u4e0b\u9762\u7684\u65b9\u6cd5\u91cd\u5199\u540e\uff0c\u6267\u884c\u65f6\u95f4\u4ece1.58\u79d2\u964d\u4f4e\u52302\u6beb\u79d2\u3002<\/p>\n\n\n\n
SELECT *\nFROM   ((SELECT *\n         FROM   my_order o\n                INNER JOIN my_appraise a\n                        ON a.orderid = o.id\n                           AND is_reply = 0\n         ORDER  BY appraise_time DESC\n         LIMIT  0, 20)\n        UNION ALL\n        (SELECT *\n         FROM   my_order o\n                INNER JOIN my_appraise a\n                        ON a.orderid = o.id\n                           AND is_reply = 1\n         ORDER  BY appraise_time DESC\n         LIMIT  0, 20)) t\nORDER  BY  is_reply ASC,\n          appraisetime DESC\nLIMIT  20;<\/pre>\n\n\n\n
5\u3001EXISTS\u8bed\u53e5<\/strong><\/p>\n\n\n\n
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MySQL \u5bf9\u5f85 EXISTS \u5b50\u53e5\u65f6\uff0c\u4ecd\u7136\u91c7\u7528\u5d4c\u5957\u5b50\u67e5\u8be2\u7684\u6267\u884c\u65b9\u5f0f\u3002\u5982\u4e0b\u9762\u7684 SQL \u8bed\u53e5\uff1a<\/p>\n\n\n\n
SELECT *\nFROM   my_neighbor n\n       LEFT JOIN my_neighbor_apply sra\n              ON n.id = sra.neighbor_id\n                 AND sra.user_id = 'xxx'\nWHERE  n.topic_status < 4\n       AND EXISTS(SELECT 1\n                  FROM   message_info m\n                  WHERE  n.id = m.neighbor_id\n                         AND m.inuser = 'xxx')\n       AND n.topic_type <> 5\n<\/pre>\n\n\n\n
\u6267\u884c\u8ba1\u5212\u4e3a\uff1a<\/p>\n\n\n\n
+----+--------------------+-------+------+-----+------------------------------------------+---------+-------+---------+ -----+\n| id | select_type        | table | type | possible_keys     | key   | key_len | ref   | rows    | Extra   |\n+----+--------------------+-------+------+ -----+------------------------------------------+---------+-------+---------+ -----+\n|  1 | PRIMARY            | n     | ALL  |  | NULL     | NULL    | NULL  | 1086041 | Using where                   |\n|  1 | PRIMARY            | sra   | ref  |  | idx_user_id | 123     | const |       1 | Using where          |\n|  2 | DEPENDENT SUBQUERY | m     | ref  |  | idx_message_info   | 122     | const |       1 | Using index condition; Using where |\n+----+--------------------+-------+------+ -----+------------------------------------------+---------+-------+---------+ -----+\n<\/pre>\n\n\n\n
\u53bb\u6389 exists \u66f4\u6539\u4e3a join\uff0c\u80fd\u591f\u907f\u514d\u5d4c\u5957\u5b50\u67e5\u8be2\uff0c\u5c06\u6267\u884c\u65f6\u95f4\u4ece1.93\u79d2\u964d\u4f4e\u4e3a1\u6beb\u79d2\u3002<\/p>\n\n\n\n
SELECT *\nFROM   my_neighbor n\n       INNER JOIN message_info m\n               ON n.id = m.neighbor_id\n                  AND m.inuser = 'xxx'\n       LEFT JOIN my_neighbor_apply sra\n              ON n.id = sra.neighbor_id\n                 AND sra.user_id = 'xxx'\nWHERE  n.topic_status < 4\n       AND n.topic_type <> 5\n<\/pre>\n\n\n\n
\u65b0\u7684\u6267\u884c\u8ba1\u5212\uff1a<\/p>\n\n\n\n
+----+-------------+-------+--------+ -----+------------------------------------------+---------+ -----+------+ -----+\n| id | select_type | table | type   | possible_keys     | key       | key_len | ref   | rows | Extra                 |\n+----+-------------+-------+--------+ -----+------------------------------------------+---------+ -----+------+ -----+\n|  1 | SIMPLE      | m     | ref    | | idx_message_info   | 122     | const    |    1 | Using index condition |\n|  1 | SIMPLE      | n     | eq_ref | | PRIMARY   | 122     | ighbor_id |    1 | Using where      |\n|  1 | SIMPLE      | sra   | ref    | | idx_user_id | 123     | const     |    1 | Using where           |\n+----+-------------+-------+--------+ -----+------------------------------------------+---------+ -----+------+ -----+\n<\/pre>\n\n\n\n
6\u3001\u6761\u4ef6\u4e0b\u63a8<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u5916\u90e8\u67e5\u8be2\u6761\u4ef6\u4e0d\u80fd\u591f\u4e0b\u63a8\u5230\u590d\u6742\u7684\u89c6\u56fe\u6216\u5b50\u67e5\u8be2\u7684\u60c5\u51b5\u6709\uff1a<\/p>\n\n\n\n
1\u3001\u805a\u5408\u5b50\u67e5\u8be2\uff1b 2\u3001\u542b\u6709 LIMIT \u7684\u5b50\u67e5\u8be2\uff1b 3\u3001UNION \u6216 UNION ALL \u5b50\u67e5\u8be2\uff1b 4\u3001\u8f93\u51fa\u5b57\u6bb5\u4e2d\u7684\u5b50\u67e5\u8be2\uff1b<\/p>\n\n\n\n
\u5982\u4e0b\u9762\u7684\u8bed\u53e5\uff0c\u4ece\u6267\u884c\u8ba1\u5212\u53ef\u4ee5\u770b\u51fa\u5176\u6761\u4ef6\u4f5c\u7528\u4e8e\u805a\u5408\u5b50\u67e5\u8be2\u4e4b\u540e\uff1a<\/p>\n\n\n\n
SELECT *\nFROM   (SELECT target,\n               Count(*)\n        FROM   operation\n        GROUP  BY target) t\nWHERE  target = 'rm-xxxx'<\/pre>\n\n\n\n
+----+-------------+------------+-------+---------------+-------------+---------+-------+------+-------------+\n| id | select_type | table      | type  | possible_keys | key         | key_len | ref   | rows | Extra       |\n+----+-------------+------------+-------+---------------+-------------+---------+-------+------+-------------+\n|  1 | PRIMARY     | <derived2> | ref   | <auto_key0>   | <auto_key0> | 514     | const |    2 | Using where |\n|  2 | DERIVED     | operation  | index | idx_4         | idx_4       | 519     | NULL  |   20 | Using index |\n+----+-------------+------------+-------+---------------+-------------+---------+-------+------+-------------+\n<\/pre>\n\n\n\n
\u786e\u5b9a\u4ece\u8bed\u4e49\u4e0a\u67e5\u8be2\u6761\u4ef6\u53ef\u4ee5\u76f4\u63a5\u4e0b\u63a8\u540e\uff0c\u91cd\u5199\u5982\u4e0b\uff1a<\/p>\n\n\n\n
SELECT target,\n       Count(*)\nFROM   operation\nWHERE  target = 'rm-xxxx'\nGROUP  BY target<\/pre>\n\n\n\n
\u6267\u884c\u8ba1\u5212\u53d8\u4e3a\uff1a<\/p>\n\n\n\n
+----+-------------+-----------+------+---------------+-------+---------+-------+------+--------------------+\n| id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra |\n+----+-------------+-----------+------+---------------+-------+---------+-------+------+--------------------+\n| 1 | SIMPLE | operation | ref | idx_4 | idx_4 | 514 | const | 1 | Using where; Using index |\n+----+-------------+-----------+------+---------------+-------+---------+-------+------+--------------------+\n<\/pre>\n\n\n\n
7\u3001\u63d0\u524d\u7f29\u5c0f\u8303\u56f4<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u5148\u4e0a\u521d\u59cb SQL \u8bed\u53e5\uff1a<\/p>\n\n\n\n
SELECT *\nFROM   my_order o\n       LEFT JOIN my_userinfo u\n              ON o.uid = u.uid\n       LEFT JOIN my_productinfo p\n              ON o.pid = p.pid\nWHERE  ( o.display = 0 )\n       AND ( o.ostaus = 1 )\nORDER  BY o.selltime DESC\nLIMIT  0, 15\n<\/pre>\n\n\n\n
\u8be5SQL\u8bed\u53e5\u539f\u610f\u662f\uff1a\u5148\u505a\u4e00\u7cfb\u5217\u7684\u5de6\u8fde\u63a5\uff0c\u7136\u540e\u6392\u5e8f\u53d6\u524d15\u6761\u8bb0\u5f55\u3002\u4ece\u6267\u884c\u8ba1\u5212\u4e5f\u53ef\u4ee5\u770b\u51fa\uff0c\u6700\u540e\u4e00\u6b65\u4f30\u7b97\u6392\u5e8f\u8bb0\u5f55\u6570\u4e3a90\u4e07\uff0c\u65f6\u95f4\u6d88\u8017\u4e3a12\u79d2\u3002<\/p>\n\n\n\n
+----+-------------+-------+--------+---------------+---------+---------+-----------------+--------+----------------------------------------------------+\n| id | select_type | table | type   | possible_keys | key     | key_len | ref             | rows   | Extra                                              |\n+----+-------------+-------+--------+---------------+---------+---------+-----------------+--------+----------------------------------------------------+\n|  1 | SIMPLE      | o     | ALL    | NULL          | NULL    | NULL    | NULL            | 909119 | Using where; Using temporary; Using filesort       |\n|  1 | SIMPLE      | u     | eq_ref | PRIMARY       | PRIMARY | 4       | o.uid |      1 | NULL                                               |\n|  1 | SIMPLE      | p     | ALL    | PRIMARY       | NULL    | NULL    | NULL            |      6 | Using where; Using join buffer (Block Nested Loop) |\n+----+-------------+-------+--------+---------------+---------+---------+-----------------+--------+----------------------------------------------------+\n<\/pre>\n\n\n\n
\u7531\u4e8e\u6700\u540e WHERE \u6761\u4ef6\u4ee5\u53ca\u6392\u5e8f\u5747\u9488\u5bf9\u6700\u5de6\u4e3b\u8868\uff0c\u56e0\u6b64\u53ef\u4ee5\u5148\u5bf9 my_order \u6392\u5e8f\u63d0\u524d\u7f29\u5c0f\u6570\u636e\u91cf\u518d\u505a\u5de6\u8fde\u63a5\u3002SQL \u91cd\u5199\u540e\u5982\u4e0b\uff0c\u6267\u884c\u65f6\u95f4\u7f29\u5c0f\u4e3a1\u6beb\u79d2\u5de6\u53f3\u3002<\/p>\n\n\n\n
SELECT *\nFROM (\nSELECT *\nFROM   my_order o\nWHERE  ( o.display = 0 )\n       AND ( o.ostaus = 1 )\nORDER  BY o.selltime DESC\nLIMIT  0, 15\n) o\n     LEFT JOIN my_userinfo u\n              ON o.uid = u.uid\n     LEFT JOIN my_productinfo p\n              ON o.pid = p.pid\nORDER BY  o.selltime DESC\nlimit 0, 15<\/pre>\n\n\n\n
\u518d\u68c0\u67e5\u6267\u884c\u8ba1\u5212\uff1a\u5b50\u67e5\u8be2\u7269\u5316\u540e\uff08select_type=DERIVED)\u53c2\u4e0e JOIN\u3002\u867d\u7136\u4f30\u7b97\u884c\u626b\u63cf\u4ecd\u7136\u4e3a90\u4e07\uff0c\u4f46\u662f\u5229\u7528\u4e86\u7d22\u5f15\u4ee5\u53ca LIMIT \u5b50\u53e5\u540e\uff0c\u5b9e\u9645\u6267\u884c\u65f6\u95f4\u53d8\u5f97\u5f88\u5c0f\u3002<\/p>\n\n\n\n
+----+-------------+------------+--------+---------------+---------+---------+-------+--------+----------------------------------------------------+\n| id | select_type | table      | type   | possible_keys | key     | key_len | ref   | rows   | Extra                                              |\n+----+-------------+------------+--------+---------------+---------+---------+-------+--------+----------------------------------------------------+\n|  1 | PRIMARY     | <derived2> | ALL    | NULL          | NULL    | NULL    | NULL  |     15 | Using temporary; Using filesort                    |\n|  1 | PRIMARY     | u          | eq_ref | PRIMARY       | PRIMARY | 4       | o.uid |      1 | NULL                                               |\n|  1 | PRIMARY     | p          | ALL    | PRIMARY       | NULL    | NULL    | NULL  |      6 | Using where; Using join buffer (Block Nested Loop) |\n|  2 | DERIVED     | o          | index  | NULL          | idx_1   | 5       | NULL  | 909112 | Using where                                        |\n+----+-------------+------------+--------+---------------+---------+---------+-------+--------+----------------------------------------------------+\n<\/pre>\n\n\n\n
8\u3001\u4e2d\u95f4\u7ed3\u679c\u96c6\u4e0b\u63a8<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u518d\u6765\u770b\u4e0b\u9762\u8fd9\u4e2a\u5df2\u7ecf\u521d\u6b65\u4f18\u5316\u8fc7\u7684\u4f8b\u5b50(\u5de6\u8fde\u63a5\u4e2d\u7684\u4e3b\u8868\u4f18\u5148\u4f5c\u7528\u67e5\u8be2\u6761\u4ef6)\uff1a<\/p>\n\n\n\n
SELECT    a.*,\n          c.allocated\nFROM      (\n              SELECT   resourceid\n              FROM     my_distribute d\n                   WHERE    isdelete = 0\n                   AND      cusmanagercode = '1234567'\n                   ORDER BY salecode limit 20) a\nLEFT JOIN\n          (\n              SELECT   resourcesid\uff0c sum(ifnull(allocation, 0) * 12345) allocated\n              FROM     my_resources\n                   GROUP BY resourcesid) c\nON        a.resourceid = c.resourcesid\n<\/pre>\n\n\n\n
\u90a3\u4e48\u8be5\u8bed\u53e5\u8fd8\u5b58\u5728\u5176\u5b83\u95ee\u9898\u5417\uff1f\u4e0d\u96be\u770b\u51fa\u5b50\u67e5\u8be2 c \u662f\u5168\u8868\u805a\u5408\u67e5\u8be2\uff0c\u5728\u8868\u6570\u91cf\u7279\u522b\u5927\u7684\u60c5\u51b5\u4e0b\u4f1a\u5bfc\u81f4\u6574\u4e2a\u8bed\u53e5\u7684\u6027\u80fd\u4e0b\u964d\u3002<\/p>\n\n\n\n
\u5176\u5b9e\u5bf9\u4e8e\u5b50\u67e5\u8be2 c\uff0c\u5de6\u8fde\u63a5\u6700\u540e\u7ed3\u679c\u96c6\u53ea\u5173\u5fc3\u80fd\u548c\u4e3b\u8868 resourceid \u80fd\u5339\u914d\u7684\u6570\u636e\u3002\u56e0\u6b64\u6211\u4eec\u53ef\u4ee5\u91cd\u5199\u8bed\u53e5\u5982\u4e0b\uff0c\u6267\u884c\u65f6\u95f4\u4ece\u539f\u6765\u76842\u79d2\u4e0b\u964d\u52302\u6beb\u79d2\u3002<\/p>\n\n\n\n
SELECT    a.*,\n          c.allocated\nFROM      (\n                   SELECT   resourceid\n                   FROM     my_distribute d\n                   WHERE    isdelete = 0\n                   AND      cusmanagercode = '1234567'\n                   ORDER BY salecode limit 20) a\nLEFT JOIN\n          (\n                   SELECT   resourcesid\uff0c sum(ifnull(allocation, 0) * 12345) allocated\n                   FROM     my_resources r,\n                            (\n                                     SELECT   resourceid\n                                     FROM     my_distribute d\n                                     WHERE    isdelete = 0\n                                     AND      cusmanagercode = '1234567'\n                                     ORDER BY salecode limit 20) a\n                   WHERE    r.resourcesid = a.resourcesid\n                   GROUP BY resourcesid) c\nON        a.resourceid = c.resourcesid<\/pre>\n\n\n\n
\u4f46\u662f\u5b50\u67e5\u8be2 a \u5728\u6211\u4eec\u7684SQL\u8bed\u53e5\u4e2d\u51fa\u73b0\u4e86\u591a\u6b21\u3002\u8fd9\u79cd\u5199\u6cd5\u4e0d\u4ec5\u5b58\u5728\u989d\u5916\u7684\u5f00\u9500\uff0c\u8fd8\u4f7f\u5f97\u6574\u4e2a\u8bed\u53e5\u663e\u7684\u7e41\u6742\u3002\u4f7f\u7528 WITH \u8bed\u53e5\u518d\u6b21\u91cd\u5199\uff1a<\/p>\n\n\n\n
WITH a AS\n(\n         SELECT   resourceid\n         FROM     my_distribute d\n         WHERE    isdelete = 0\n         AND      cusmanagercode = '1234567'\n         ORDER BY salecode limit 20)\nSELECT    a.*,\n          c.allocated\nFROM      a\nLEFT JOIN\n          (\n                   SELECT   resourcesid\uff0c sum(ifnull(allocation, 0) * 12345) allocated\n                   FROM     my_resources r,\n                            a\n                   WHERE    r.resourcesid = a.resourcesid\n                   GROUP BY resourcesid) c\nON        a.resourceid = c.resourcesid<\/pre>\n\n\n\n
\u603b\u7ed3<\/strong><\/p>\n\n\n\n
\n\n\n\n
\u6570\u636e\u5e93\u7f16\u8bd1\u5668\u4ea7\u751f\u6267\u884c\u8ba1\u5212\uff0c\u51b3\u5b9a\u7740SQL\u7684\u5b9e\u9645\u6267\u884c\u65b9\u5f0f\u3002\u4f46\u662f\u7f16\u8bd1\u5668\u53ea\u662f\u5c3d\u529b\u670d\u52a1\uff0c\u6240\u6709\u6570\u636e\u5e93\u7684\u7f16\u8bd1\u5668\u90fd\u4e0d\u662f\u5c3d\u5584\u5c3d\u7f8e\u7684\u3002<\/p>\n\n\n\n
\u4e0a\u8ff0\u63d0\u5230\u7684\u591a\u6570\u573a\u666f\uff0c\u5728\u5176\u5b83\u6570\u636e\u5e93\u4e2d\u4e5f\u5b58\u5728\u6027\u80fd\u95ee\u9898\u3002\u4e86\u89e3\u6570\u636e\u5e93\u7f16\u8bd1\u5668\u7684\u7279\u6027\uff0c\u624d\u80fd\u907f\u89c4\u5176\u77ed\u5904\uff0c\u5199\u51fa\u9ad8\u6027\u80fd\u7684SQL\u8bed\u53e5\u3002<\/p>\n\n\n\n
\u7a0b\u5e8f\u5458\u5728\u8bbe\u8ba1\u6570\u636e\u6a21\u578b\u4ee5\u53ca\u7f16\u5199SQL\u8bed\u53e5\u65f6\uff0c\u8981\u628a\u7b97\u6cd5\u7684\u601d\u60f3\u6216\u610f\u8bc6\u5e26\u8fdb\u6765\u3002<\/p>\n\n\n\n
\u7f16\u5199\u590d\u6742SQL\u8bed\u53e5\u8981\u517b\u6210\u4f7f\u7528 WITH \u8bed\u53e5\u7684\u4e60\u60ef\u3002\u7b80\u6d01\u4e14\u601d\u8def\u6e05\u6670\u7684SQL\u8bed\u53e5\u4e5f\u80fd\u51cf\u5c0f\u6570\u636e\u5e93\u7684\u8d1f\u62c5 \u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
sql\u8bed\u53e5\u7684\u6267\u884c\u987a\u5e8f 1\u3001LIMIT \u8bed\u53e5 \u5206\u9875\u67e5\u8be2\u662f\u6700\u5e38\u7528\u7684\u573a\u666f\u4e4b\u4e00\uff0c\u4f46\u4e5f\u901a\u5e38\u4e5f\u662f\u6700\u5bb9\u6613\u51fa\u95ee\u9898\u7684\u5730\u65b9\u3002\u6bd4\u5982\u5bf9 […]<\/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\/13672"}],"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=13672"}],"version-history":[{"count":1,"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/posts\/13672\/revisions"}],"predecessor-version":[{"id":13675,"href":"https:\/\/92it.top\/index.php?rest_route=\/wp\/v2\/posts\/13672\/revisions\/13675"}],"wp:attachment":[{"href":"https:\/\/92it.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=13672"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/92it.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=13672"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/92it.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=13672"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}