mysql数据迁移

移动一个表的数据到新表中

保留表中is_checked=1 最后的一条数据

CREATE TABLE t_chapter_new2 AS SELECT * FROM t_chapter WHERE id IN(
SELECT a.ma FROM(SELECT jidi_id,MAX(id) ma
FROM t_chapter
WHERE is_checked = 1 GROUP BY jidi_id) a)

INSERT INTO t_chapter_new2 SELECT * FROM t_chapter WHERE is_checked!=1

联表删除：

DELETE t_chapter_new2 FROM t_chapter_new2 , t_book WHERE t_chapter_new2.is_checked != 1 AND t_chapter_new2.jidi_id = t_book.jidi_id AND t_book.flag = 'wanben'

1、从数据表t1 中把那些id值在数据表t2 里有匹配的记录全删除掉

DELETE t1 FROM t1,t2 WHERE t1.id=t2.id    或DELETE  FROM t1 USING t1,t2 WHERE t1.id=t2.id

2、从数据表t1里在数据表t2里没有匹配的记录查找出来并删除掉

DELETE t1 FROM t1 LEFT JOIN T2 ON t1.id=t2.id WHERE t2.id IS NULL 或

DELETE  FROM t1,USING t1 LEFT JOIN T2 ON t1.id=t2.id WHERE t2.id IS NULL

3、从两个表中找出相同记录的数据并把两个表中的数据都删除掉

DELETE t1,t2 from t1 LEFT JOIN t2 ON t1.id=t2.id WHERE t1.id=25

注意此处的delete t1,t2 from 中的t1,t2不能是别名

如：delete t1,t2 from table_name as t1 left join table2_name as t2 on t1.id=t2.id where table_name.id=25 在数据里面执行是错误的（MYSQL 版本不小于5.0在5.0中是可以的）

上述语句改写成

delete table_name,table2_name from table_name as t1 left join table2_name as t2 on t1.id=t2.id where table_name.id=25 在数据里面执行是错误的