MySQL--Delete语句别名+LIMIT
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MySQL--Delete语句别名+LIMIT
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在MySQL中,可以使用LIMIT来限制删除的数量,但部分写法并不支持LIMIT.
LIMIT方式
对于查询: SELECT * FROM T1 LIMIT 1; 可以转换成: DELETE FROM T1 LIMIT 1;别名方式:
## 使用别名 DELETE T FROM T1 AS T;但MySQL不支持别名+LIMIT方式,如:
查询: SELECT * FROM T1 AS T LIMIT 1; 不能转换为: DELETE T FROM T1 AS T LIMIT 1;
对于多表关联操作,同样不允许别名+LIMIT操作,但可以将LIMIT放入子查询中:
对于查询: SELECT * FROM TB_1 AS T1 LEFT JOIN TB_2 AS T2 ON T1.ID = T2.ID WHERE T2.ID IS NULL LIMIT 10;不能修改为: DELETE T1 FROM TB_1 AS T1 LEFT JOIN TB_2 AS T2 ON T1.ID = T2.ID WHERE T2.ID IS NULL LIMIT 10;
需要转换为: DELETE T1 FROM TB_1 AS T1 (SELECT T1.ID FROM TB_1 AS T1 LEFT JOIN TB_2 AS T2 ON T1.ID = T2.ID WHERE T2.ID IS NULL LIMIT 10) AS T3 INNER JOIN TB_2 AS T2 ON T1.ID=T2.ID
转载于:https://www.cnblogs.com/gaogao67/p/10391972.html
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