MySQL中快速找出無顯式主鍵的表

大家好，我是知數堂SQL 優化班老師 網名：騎龜的兔子

版本 ：Server version: 8.0.22 MySQL Community Server - GPL

目標：想要查找沒有顯示主鍵的表

第一步：查詢所有用戶表 

SELECTTABLE_SCHEMA,TABLE_NAMEFROMinformation_schema.TABLES tWHERETABLE_SCHEMA NOT IN ('mysql','sys','information_schema','performance_schema') ANDTABLE_TYPE = 'BASE TABLE';
+--------------+------------------+| TABLE_SCHEMA | TABLE_NAME       |+--------------+------------------+| employees    | departments      || employees    | dept2            || employees    | dept_emp         || employees    | dept_emp2        || employees    | dept_emp3        || employees    | dept_manager     || employees    | emp1             || employees    | emp2             || employees    | emp3             || employees    | employees        || employees    | salaries         || employees    | salaries2        || employees    | salaries3        || employees    | salaries4_up_20w || employees    | t0522            || employees    | t1               || employees    | t11              || employees    | t11_1            || employees    | t12              || employees    | t4               || employees    | t_g1             || employees    | t_group          || employees    | t_group2         || employees    | t_group21        || employees    | t_group3         || employees    | t_group4         || employees    | t_group5         || employees    | t_group6         || employees    | t_order          || employees    | t_time           || employees    | test1            || employees    | titles           || employees    | txt_t1           || test         | clone_progress   || test         | customer         || test         | district         || test         | history          || test         | item             || test         | new_orders       || test         | order_line       || test         | orders           || test         | stock            || test         | t1               || test         | t2               || test         | t3               || test         | tb_task          || test         | tb_task_order    || test         | warehouse        |+--------------+------------------+48 rows in set (0.00 sec)

第二步 ： 查找所有包含顯示主鍵的表 

SELECTTABLE_SCHEMA,TABLE_NAMEFROMinformation_schema.TABLE_CONSTRAINTS cWHERETABLE_SCHEMA NOT IN ('mysql','sys','information_schema','performance_schema') AND CONSTRAINT_TYPE = 'PRIMARY KEY'
+--------------+---------------+| TABLE_SCHEMA | TABLE_NAME    |+--------------+---------------+| employees    | departments   || employees    | dept_emp      || employees    | dept_manager  || employees    | emp1          || employees    | emp3          || employees    | employees     || employees    | salaries      || employees    | salaries3     || employees    | t1            || employees    | t11           || employees    | t12           || employees    | t_group2      || employees    | t_group21     || employees    | t_group6      || employees    | t_time        || employees    | titles        || test         | customer      || test         | district      || test         | item          || test         | new_orders    || test         | order_line    || test         | orders        || test         | stock         || test         | t1            || test         | t3            || test         | tb_task       || test         | tb_task_order || test         | warehouse     |+--------------+---------------+28 rows in set (0.00 sec)

第三步：兩個結果集進行JOIN ，找到差異

SELECTa.*, b.*FROM(SELECTTABLE_SCHEMA,TABLE_NAMEFROMinformation_schema.TABLES tWHERETABLE_SCHEMA NOT IN ('mysql','sys','information_schema','performance_schema') ANDTABLE_TYPE = 'BASE TABLE') AS aLEFT JOIN (SELECTTABLE_SCHEMA,TABLE_NAMEFROMinformation_schema.TABLE_CONSTRAINTS cWHERETABLE_SCHEMA NOT IN ('mysql','sys','information_schema','performance_schema') AND CONSTRAINT_TYPE = 'PRIMARY KEY') AS b USING (TABLE_SCHEMA, TABLE_NAME)WHEREb.TABLE_NAME IS NULL;
Empty set (0.00 sec)

同樣的思路我們在

Server version:   5.7.28-log MySQL Community Server (GPL)

SELECTTABLE_SCHEMA,TABLE_NAMEFROMinformation_schema.TABLES tWHERETABLE_SCHEMA NOT IN ('mysql','sys','information_schema','performance_schema') ANDTABLE_TYPE = 'BASE TABLE';+--------------+-------------------------+| TABLE_SCHEMA | TABLE_NAME              |+--------------+-------------------------+| employees    | departments             || employees    | dept2                   || employees    | dept_emp                || employees    | dept_emp2               || employees    | dept_emp3               || employees    | dept_manager            || employees    | emp1                    || employees    | emp2                    || employees    | emp3                    || employees    | employees               || employees    | salaries                || employees    | salaries2               || employees    | salaries3               || employees    | salaries4_up_20w        || employees    | salaries5               || employees    | salaries6               || employees    | t1                      || employees    | t11                     || employees    | t11_1                   || employees    | t4                      || employees    | t_g1                    || employees    | t_group                 || employees    | t_group2                || employees    | t_group3                || employees    | t_group4                || employees    | t_group5                || employees    | t_order                 || employees    | t_time                  || employees    | test1                   || employees    | titles                  || employees    | tmp1                    || employees    | txt_t1                  || test         | clone_progress          || test         | disk_free               || test         | l                       || test         | l2                      || test         | t1                      || test         | t2                      || test         | t_msg_history_2017_06_1 || test         | tb_task                 || test         | tb_task_order           || test         | ts_lock                 |+--------------+-------------------------+42 rows in set (0.00 sec)
SELECTTABLE_SCHEMA,TABLE_NAMEFROMinformation_schema.TABLE_CONSTRAINTS cWHERETABLE_SCHEMA NOT IN ('mysql','sys','information_schema','performance_schema') AND CONSTRAINT_TYPE = 'PRIMARY KEY'+--------------+-------------------------+| TABLE_SCHEMA | TABLE_NAME              |+--------------+-------------------------+| employees    | departments             || employees    | dept_emp                || employees    | dept_manager            || employees    | emp1                    || employees    | emp3                    || employees    | employees               || employees    | salaries                || employees    | salaries3               || employees    | salaries5               || employees    | salaries6               || employees    | t1                      || employees    | t11                     || employees    | t_time                  || employees    | titles                  || test         | disk_free               || test         | l                       || test         | l2                      || test         | t_msg_history_2017_06_1 || test         | tb_task                 || test         | tb_task_order           || test         | ts_lock                 |+--------------+-------------------------+21 rows in set (0.00 sec)
SELECTa.*, b.*FROM(SELECTTABLE_SCHEMA,TABLE_NAMEFROMinformation_schema.TABLES tWHERETABLE_SCHEMA NOT IN ('mysql','sys','information_schema','performance_schema') ANDTABLE_TYPE = 'BASE TABLE') AS aLEFT JOIN (SELECTTABLE_SCHEMA,TABLE_NAMEFROMinformation_schema.TABLE_CONSTRAINTS cWHERETABLE_SCHEMA NOT IN ('mysql','sys','information_schema','performance_schema') AND CONSTRAINT_TYPE = 'PRIMARY KEY') AS b USING (TABLE_SCHEMA, TABLE_NAME)WHEREb.TABLE_NAME IS NULL;
+--------------+------------------+--------------+------------+| TABLE_SCHEMA | TABLE_NAME       | TABLE_SCHEMA | TABLE_NAME |+--------------+------------------+--------------+------------+| employees    | dept2            | NULL         | NULL       || employees    | dept_emp2        | NULL         | NULL       || employees    | dept_emp3        | NULL         | NULL       || employees    | emp2             | NULL         | NULL       || employees    | salaries2        | NULL         | NULL       || employees    | salaries4_up_20w | NULL         | NULL       || employees    | t11_1            | NULL         | NULL       || employees    | t4               | NULL         | NULL       || employees    | t_g1             | NULL         | NULL       || employees    | t_group          | NULL         | NULL       || employees    | t_group2         | NULL         | NULL       || employees    | t_group3         | NULL         | NULL       || employees    | t_group4         | NULL         | NULL       || employees    | t_group5         | NULL         | NULL       || employees    | t_order          | NULL         | NULL       || employees    | test1            | NULL         | NULL       || employees    | tmp1             | NULL         | NULL       || employees    | txt_t1           | NULL         | NULL       || test         | clone_progress   | NULL         | NULL       || test         | t1               | NULL         | NULL       || test         | t2               | NULL         | NULL       |+--------------+------------------+--------------+------------+21 rows in set (0.01 sec)

可以看到在5.7中就可以得到我們想要的答案，但8.0.22中就不行。

我們現在開始分析其原因，首先我們來比較下不同版本之間的SQL的執行計劃。

5.7

+----+-------------+-------+------------+------+---------------+------+---------+------+------+----------+--------------------------------------------------------------------------------------------+| id | select_type | table | partitions | type | possible_keys | key  | key_len | ref  | rows | filtered | Extra                                                                                      |+----+-------------+-------+------------+------+---------------+------+---------+------+------+----------+--------------------------------------------------------------------------------------------+|  1 | SIMPLE      | t     | NULL       | ALL  | NULL          | NULL | NULL    | NULL | NULL |     NULL | Using where; Open_frm_only; Scanned all databases                                          ||  1 | SIMPLE      | c     | NULL       | ALL  | NULL          | NULL | NULL    | NULL | NULL |     NULL | Using where; Open_full_table; Scanned all databases; Using join buffer (Block Nested Loop) |+----+-------------+-------+------------+------+---------------+------+---------+------+------+----------+--------------------------------------------------------------------------------------------+2 rows in set, 1 warning (0.01 sec)[email protected]>[employees]>show warnings\G*************************** 1. row ***************************  Level: Note   Code: 1003Message: /* select#1 */ select `t`.`TABLE_SCHEMA` AS `TABLE_SCHEMA`,`t`.`TABLE_NAME` AS `TABLE_NAME`,`c`.`TABLE_SCHEMA` AS `TABLE_SCHEMA`,`c`.`TABLE_NAME` AS `TABLE_NAME` from `information_schema`.`tables` `t` left join (`information_schema`.`table_constraints` `c`) on(((`c`.`TABLE_NAME` = `t`.`TABLE_NAME`) and (`c`.`TABLE_SCHEMA` = `t`.`TABLE_SCHEMA`) and (`t`.`TABLE_SCHEMA` not in ('mysql','sys','information_schema','performance_schema')) and (`c`.`CONSTRAINT_TYPE` = 'PRIMARY KEY'))) where (isnull(`c`.`TABLE_NAME`) and (`t`.`TABLE_SCHEMA` not in ('mysql','sys','information_schema','performance_schema')) and (`t`.`TABLE_TYPE` = 'BASE TABLE'))1 row in set (0.00 sec)

我們可以看到解析到的SQL 中包含 isnull(`c`.`TABLE_NAME`) 

8.0

+----+-------------------+------------+------------+--------+-----------------------+-------------+---------+-------------------------------+------+----------+-----------------------------------------+| id | select_type       | table      | partitions | type   | possible_keys         | key         | key_len | ref                           | rows | filtered | Extra                                   |+----+-------------------+------------+------------+--------+-----------------------+-------------+---------+-------------------------------+------+----------+-----------------------------------------+|  1 | PRIMARY           | cat        | NULL       | index  | PRIMARY               | name        | 194     | NULL                          |    1 |   100.00 | Using index                             ||  1 | PRIMARY           | sch        | NULL       | ref    | PRIMARY,catalog_id    | catalog_id  | 8       | mysql.cat.id                  |    6 |   100.00 | Using where; Using index                ||  1 | PRIMARY           | tbl        | NULL       | ref    | schema_id,type,type_2 | schema_id   | 8       | mysql.sch.id                  |   47 |    67.78 | Using where                             ||  1 | PRIMARY           | col        | NULL       | eq_ref | PRIMARY               | PRIMARY     | 8       | mysql.tbl.collation_id        |    1 |   100.00 | Using index                             ||  1 | PRIMARY           | ts         | NULL       | eq_ref | PRIMARY               | PRIMARY     | 8       | mysql.tbl.tablespace_id       |    1 |   100.00 | Using index                             ||  1 | PRIMARY           | stat       | NULL       | eq_ref | PRIMARY               | PRIMARY     | 388     | mysql.sch.name,mysql.tbl.name |    1 |   100.00 | Using where; Using index                ||  1 | PRIMARY           | cat        | NULL       | index  | PRIMARY               | name        | 194     | NULL                          |    1 |   100.00 | Using index                             ||  1 | PRIMARY           | sch        | NULL       | eq_ref | PRIMARY,catalog_id    | catalog_id  | 202     | mysql.cat.id,func             |    1 |   100.00 | Using where; Using index                ||  1 | PRIMARY           | tbl        | NULL       | eq_ref | schema_id             | schema_id   | 202     | mysql.sch.id,func             |    1 |   100.00 | Using where; Rematerialize (<derived6>) ||  1 | PRIMARY           | <derived6> | NULL       | ref    | <auto_key0>           | <auto_key0> | 35      | const                         |    1 |   100.00 | NULL                                    ||  6 | DEPENDENT DERIVED | idx        | NULL       | ref    | table_id              | table_id    | 8       | mysql.tbl.id                  |    1 |    40.00 | Using where                             ||  7 | DEPENDENT UNION   | fk         | NULL       | ref    | table_id              | table_id    | 8       | mysql.tbl.id                  |    2 |   100.00 | Using index                             ||  8 | DEPENDENT UNION   | cc         | NULL       | ref    | table_id              | table_id    | 8       | mysql.tbl.id                  |    1 |   100.00 | NULL                                    |+----+-------------------+------------+------------+--------+-----------------------+-------------+---------+-------------------------------+------+----------+-----------------------------------------+13 rows in set, 5 warnings (0.00 sec)
Message: /* select#1 */ select (`sch`.`name` collate utf8_tolower_ci) AS `TABLE_SCHEMA`,(`tbl`.`name` collate utf8_tolower_ci) AS `TABLE_NAME`,(`mysql`.`sch`.`name` collate utf8_tolower_ci) AS `TABLE_SCHEMA`,(`mysql`.`tbl`.`name` collate utf8_tolower_ci) AS `TABLE_NAME` from `mysql`.`tables` `tbl` join `mysql`.`schemata` `sch` join `mysql`.`catalogs` `cat` left join `mysql`.`collations` `col` on((`col`.`id` = `tbl`.`collation_id`)) left join `mysql`.`tablespaces` `ts` on((`ts`.`id` = `tbl`.`tablespace_id`)) left join `mysql`.`table_stats` `stat` on(((`tbl`.`name` = `stat`.`table_name`) and (`sch`.`name` = `stat`.`schema_name`))) left join (`mysql`.`tables` `tbl` join `mysql`.`schemata` `sch` join `mysql`.`catalogs` `cat` join lateral (/* select#6 */ select `mysql`.`idx`.`name` AS `CONSTRAINT_NAME`,if((`mysql`.`idx`.`type` = 'PRIMARY'),'PRIMARY KEY',`mysql`.`idx`.`type`) AS `CONSTRAINT_TYPE`,'YES' AS `ENFORCED` from `mysql`.`indexes` `idx` where ((`mysql`.`idx`.`table_id` = `mysql`.`tbl`.`id`) and (`mysql`.`idx`.`type` in ('PRIMARY','UNIQUE')) and (0 <> is_visible_dd_object(`mysql`.`tbl`.`hidden`,`mysql`.`idx`.`hidden`))) union all /* select#7 */ select (`mysql`.`fk`.`name` collate utf8_tolower_ci) AS `CONSTRAINT_NAME`,'FOREIGN KEY' AS `CONSTRAINT_TYPE`,'YES' AS `ENFORCED`from `mysql`.`foreign_keys` `fk` where (`mysql`.`fk`.`table_id` = `mysql`.`tbl`.`id`) union all /* select#8 */ select `mysql`.`cc`.`name` AS `CONSTRAINT_NAME`,'CHECK' AS `CONSTRAINT_TYPE`,`mysql`.`cc`.`enforced` AS `ENFORCED` from `mysql`.`check_constraints` `cc` where (`mysql`.`cc`.`table_id` = `mysql`.`tbl`.`id`)) `constraints`) on(((`mysql`.`tbl`.`schema_id` = `mysql`.`sch`.`id`) and (`mysql`.`sch`.`catalog_id` = `mysql`.`cat`.`id`) and (`constraints`.`CONSTRAINT_TYPE` = 'PRIMARY KEY') and ((`mysql`.`sch`.`name` collate utf8_tolower_ci) not in ('mysql','sys','information_schema','performance_schema')) and ((`sch`.`name` collate utf8_tolower_ci) = (`mysql`.`sch`.`name` collate utf8_tolower_ci)) and ((`tbl`.`name` collate utf8_tolower_ci) = (`mysql`.`tbl`.`name` collate utf8_tolower_ci)) and (0 <> can_access_table(`mysql`.`sch`.`name`,`mysql`.`tbl`.`name`)) and (0 <> is_visible_dd_object(`mysql`.`tbl`.`hidden`)))) where ((`tbl`.`schema_id` = `sch`.`id`) and (`sch`.`catalog_id` = `cat`.`id`) and (`tbl`.`type` = 'BASE TABLE') and ((`mysql`.`tbl`.`name` collate utf8_tolower_ci) is null) and ((`sch`.`name` collate utf8_tolower_ci) not in ('mysql','sys','information_schema','performance_schema')) and (0 <> can_access_table(`sch`.`name`,`tbl`.`name`)) and (0 <> is_visible_dd_object(`tbl`.`hidden`)))5 rows in set (0.00 sec)

從解析到的SQL中我們沒有發現 TABLE_NAME IS NULL;

相關的內容！說明在解析的過程中由於優化器的問題 解析錯誤了 ！

我們把視圖合併功能先關下看看 

set session optimizer_switch='derived_merge=off'
Message: /* select#1 */ select `a`.`TABLE_SCHEMA` AS `TABLE_SCHEMA`,`a`.`TABLE_NAME` AS `TABLE_NAME`,`b`.`TABLE_SCHEMA` AS `TABLE_SCHEMA`,`b`.`TABLE_NAME` AS `TABLE_NAME` from (/* select#2 */ select `information_schema`.`t`.`TABLE_SCHEMA` AS `TABLE_SCHEMA`,`information_schema`.`t`.`TABLE_NAME` AS `TABLE_NAME` from `information_schema`.`TABLES` `t`) `a` left join (/* select#3 */ select `information_schema`.`c`.`TABLE_SCHEMA` AS `TABLE_SCHEMA`,`information_schema`.`c`.`TABLE_NAME` AS `TABLE_NAME` from `information_schema`.`TABLE_CONSTRAINTS` `c`) `b` on(((`b`.`TABLE_NAME` = `a`.`TABLE_NAME`) and (`b`.`TABLE_SCHEMA` = `a`.`TABLE_SCHEMA`))) where (`b`.`TABLE_NAME` is null)5 rows in set (0.00 sec)
+--------------+------------------+--------------+------------+| TABLE_SCHEMA | TABLE_NAME       | TABLE_SCHEMA | TABLE_NAME |+--------------+------------------+--------------+------------+| employees    | dept2            | NULL         | NULL       || employees    | dept_emp2        | NULL         | NULL       || employees    | dept_emp3        | NULL         | NULL       || employees    | emp2             | NULL         | NULL       || employees    | salaries2        | NULL         | NULL       || employees    | salaries4_up_20w | NULL         | NULL       || employees    | t0522            | NULL         | NULL       || employees    | t11_1            | NULL         | NULL       || employees    | t4               | NULL         | NULL       || employees    | t_g1             | NULL         | NULL       || employees    | t_group          | NULL         | NULL       || employees    | t_group3         | NULL         | NULL       || employees    | t_group4         | NULL         | NULL       || employees    | t_group5         | NULL         | NULL       || employees    | t_order          | NULL         | NULL       || employees    | test1            | NULL         | NULL       || employees    | txt_t1           | NULL         | NULL       || test         | clone_progress   | NULL         | NULL       || test         | history          | NULL         | NULL       || test         | t2               | NULL         | NULL       |+--------------+------------------+--------------+------------+20 rows in set (0.00 sec)

結果發現 TABLE_NAME IS NULL;

又出現了！！最終發現是視圖合併搞的鬼 ！視圖合併功能是5.7添加的，非常好，但是有時候 就會出現一些問題，但是掌握解決問題的方法和思路，就會從容應對！

我的新一輪的SQL 優化課 即將在春節後開課 

我是知數堂SQL 優化班老師~ ^^

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