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MySQL5.7新特性之explain UPDATE/DELETE/INSERT

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在MySQL5.5版本中，explain查看执行计划，只能支持select语句，但是在MySQL5.6/5.7版本中，可以支持DML语句，即UPDATE、DELETE、INSERT。
 建立测试表accessLog和accessLog_bak进行测试：

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  1. mysql> explain select * from accessLog where id=16649850;
  2. +----+-------------+-----------+------------+-------+---------------+---------+---------+-------+------+----------+-------+
  3. | id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
  4. +----+-------------+-----------+------------+-------+---------------+---------+---------+-------+------+----------+-------+
  5. | 1 | SIMPLE | accessLog | NULL | const | PRIMARY | PRIMARY | 8 | const | 1 | 100.00 | NULL |
  6. +----+-------------+-----------+------------+-------+---------------+---------+---------+-------+------+----------+-------+
  7. 1 row in set, 1 warning (0.00 sec)

  9. mysql> explain delete from accessLog where id=16649850;
  10. +----+-------------+-----------+------------+-------+---------------+---------+---------+-------+------+----------+-------------+
  11. | id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
  12. +----+-------------+-----------+------------+-------+---------------+---------+---------+-------+------+----------+-------------+
  13. | 1 | DELETE | accessLog | NULL | range | PRIMARY | PRIMARY | 8 | const | 1 | 100.00 | Using where |
  14. +----+-------------+-----------+------------+-------+---------------+---------+---------+-------+------+----------+-------------+
  15. 1 row in set (0.00 sec)

  17. mysql> explain update accessLog_bak set id=111 where id=16649867;
  18. +----+-------------+---------------+------------+------+---------------+------+---------+------+--------+----------+-------------+
  19. | id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
  20. +----+-------------+---------------+------------+------+---------------+------+---------+------+--------+----------+-------------+
  21. | 1 | UPDATE | accessLog_bak | NULL | ALL | NULL | NULL | NULL | NULL | 582486 | 100.00 | Using where |
  22. +----+-------------+---------------+------------+------+---------------+------+---------+------+--------+----------+-------------+
  23. 1 row in set (0.02 sec)

  25. mysql> explain insert into accessLog select * from accessLog_bak where id=111;
  26. +----+-------------+---------------+------------+------+---------------+------+---------+------+--------+----------+-------------+
  27. | id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |
  28. +----+-------------+---------------+------------+------+---------------+------+---------+------+--------+----------+-------------+
  29. | 1 | INSERT | accessLog | NULL | ALL | NULL | NULL | NULL | NULL | NULL | NULL | NULL |
  30. | 1 | SIMPLE | accessLog_bak | NULL | ALL | NULL | NULL | NULL | NULL | 582486 | 10.00 | Using where |
  31. +----+-------------+---------------+------------+------+---------------+------+---------+------+--------+----------+-------------+
  32. 2 rows in set (0.02 sec)


标签：INSERT,accessLog,MySQL5.7,UPDATE,key,NULL,type,id,select
来源： https://blog.51cto.com/u_12592884/2693908