MySql:多表关联的批量更新与删除方法
大概总结一下关于多表关联的批量更新与删除方法和注意事项
执行方法格式如下：
一、join...on...写法
update——UPDATE TABLE_1 A, TABLE_2 AS B SET A.PARAM_VALUE = 1, B.PARAM_VALUE = 1 WHERE A.TID = B.TID AND 1 = 1;
delete——DELETE TABLE_1 AS A, TABLE_2 AS B FROM TABLE_1 AS A, TABLE_2 AS B WHERE A.TID = B.TID AND 1 = 1;
二、where a.id = b.id 链接写法
update——UPDATE TABLE_1 AS A LEFT JOIN TABLE_2 B ON A.TID = B.TID SET A.PARAM_VALUE = 0 WHERE 1 = 1;
delete——DELETE TABLE_1 AS A, TABLE_2 AS B FROM TABLE_1 AS A LEFT JOIN TABLE_2 AS B ON A.TID = B.TID WHERE 1 = 1;
注意事项： 1、尽量不要用IN来包含ID标识执行查询，那样会使索引失效 2、执行语句之前先用SELECT查询获取COUNT看执行前后是否一致
注意事项： 1、尽量不要用IN来包含ID标识执行查询，那样会使索引失效 2、执行语句之前先用SELECT查询获取COUNT看执行前后是否一致
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