Question

我有以下SQL

从TempTable中选择count（*）col，column1，column2，column3 按column1，column2，column3分组按顺序排列

所以计数生成的列将返回一个数字，并且有17行没有数字1（重复的行作为列1,2和3是主键）我想要删除任何有计数的行大于1？

Answer 1

您可以使用having-clause：

select count(*) col, column1, column2, column3
from TempTable group by column1, column2, column3
having count(*) > 1
order by 1 desc

要删除：

delete tt
from TempTable tt
     inner join (select count(*) col, column1, column2, column3
                 from TempTable group by column1, column2, column3
                 having count(*) > 1) tmp
     on tmp.column1 = tt.column1
     and tmp.column2 = tt.column2
     and tmp.column3 = tt.column3

Answer 2

首先在临时表中插入数据：

select count(*) col, column1, column2, column3
into #temp
from TempTable group by column1, column2, column3 order by 1 desc

然后，删除数据，并从#temp表中插入：

delete from TempTable 
go

insert into TempTable select column1, column2, column3 from #temp
go

如何在SQL中访问函数生成列的值

2 个答案: