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下面这段代码什么意思,主要是后面条件

来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:综合作业 时间:2024/05/15 15:48:49
下面这段代码什么意思,主要是后面条件
delete from ware
where ware_wareid in (select ware_wareid from ware where ware_deleted is null group by ware_wareid having count(ware_wareid) > 1)
and rowid not in (select min(rowid) from ware where ware_deleted is null group by ware_wareid having count(ware_wareid )>1)
下面这段代码什么意思,主要是后面条件
将表ware中,字段ware_deleted值为空的记录选出来,再选择ware_wareid有重复的记录,再从里面将rowid最小的剔除后,其余的记录全部删除.
delete from ware
where ware_wareid in -- 其余的记录全部删除
(select ware_wareid
from ware
where ware_deleted is null -- 字段ware_deleted值为空
group by ware_wareid
having count(ware_wareid) > 1) -- 选择ware_wareid有重复的记录
and rowid not in -- 将rowid最小的剔除后
(select min(rowid)
from ware
where ware_deleted is null -- 字段ware_deleted值为空
group by ware_wareid
having count(ware_wareid )>1) -- 选择ware_wareid有重复的记录