Question

有两个表：report（具有reportId的主键和名为migrated的位字段）和report_detail（具有reportId的外键）。我想从report_detail中删除所有具有reportId的行，该报告在报告表中已迁移= 1.这是选择我想要的所有行的select查询：

select * 
from report r inner join report_detail d 
    on r.reportId = d.reportId 
where migrated = 1

这个删除查询会执行我想要的操作还是我做错了什么？

delete from report_detail
where exists(
    select * 
    from report r inner join report_detail d 
        on r.reportId = d.reportId 
    where migrated = 1
)

Answer 1

DELETE FROM report_detail
WHERE 
    report_detail.reportId IN
    (
        SELECT reportId 
        FROM report 
        WHERE migrated = 1
    )

Answer 2

这可能会删除表格中的所有内容。

试试这个：

delete d 
from report_detail d 
inner join report r  
    on r.reportId = d.reportId  
where migrated = 1

Answer 3

delete from report_detail d 
inner join report r 
on r.reportId = d.reportId 
where migrated = 1

Answer 4

在与其他表连接时，MySQL可以从特定表中delete：

DELETE t1, t2 FROM t1 INNER JOIN t2 INNER JOIN t3
WHERE t1.id=t2.id AND t2.id=t3.id;

或者：

DELETE FROM t1, t2 USING t1 INNER JOIN t2 INNER JOIN t3
WHERE t1.id=t2.id AND t2.id=t3.id;

我有一个SQL删除查询

4 个答案: