Unknown column 'o1.name' in 'where clause'

Question

select * from test AS o1 where 
(select count(1) from
(select count(1) from test  where 
 name=o1.name group by age)aa)=1

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please verify my account

Answer 1

没看懂你想干嘛，这么写肯定出错

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想不想时已是想，不如不想都不想。

Answer 2

SQL Server 里面大致没问题，加个列名就行，没有棂主的那个错误

DECLARE @test TABLE(name sysname, age varchar(10));
select * from @test AS o1 where 
(select count(1) from
(select count(1) as 这里要个列名 from @test  where
 name=o1.name group by age)aa)=1

Answer 3

mysql 里面有这个问题，它的子查询比较弱

不过你可以用 count(distinct 少嵌套一次，这样就没问题了

select * from test AS o1 where
(select count(distinct age) from test  where
 name=o1.name )=1