在SQL中使用不同的条件两次获取相同的列

Question

我想两次检索相同的列，但条件不同。

我的查询是这样的，但以下查询将检索两个不同的列。但我希望两次获得同一列，我怎样才能实现这一目标？

Select name from tbCustomer where ID in (select ID from tbOldCustomer where oldID= 1)
Select name from tbCustomer where ID in (select ID from tbOldCustomer where oldID= 2)

tbCustomer有两列： ID名称 1 aaa 2 bbb 3 ccc 4 ddd

tbOldCustomer有两列：

ID oldID 1 2 2 1 3 1 4 2 4 1

想得到名称，其中oldID在（1,2）中，输出应该是以下内容：

名称1 bbb aaa ccc ddd DDD

Answer 1

我认为你可以通过使用简单的JOIN实现这一目标

Select name 
from tbCustomer tc 
inner join tbOldCustomer toc On toc.id = tc.id
where toc.oldID IN (1,2)

Answer 2

使用存在

select t1.name 
from tbCustomer t1 
exists( select 1 from  tbOldCustomer t2  where  t1.id = t2.id
                                       and t2.oldid in (1,2)
        )

Answer 3

你可以尝试使用conditional aggregation与case when expression

select max(case when oldID= 1 then name end) as name1,
       max(case when oldID= 2 then name end) as name2
from tbCustomer join tbOldCustomer on ID=oldID where oldid in (1,2)
group by oldid

Answer 4

你得试试

Select tc.name, toc.name from tbCustomer tc inner join 
tbOldCustomer toc On toc.id = c.id where toc.oldID IN (1,2)

Answer 5

请试试这个。

Select name from tbCustomer where ID in (select ID from tbOldCustomer where oldID IN(1,2))

要么

Select A.name from tbCustomer A
INNER JOIN tbOldCustomer  B
ON A.id = B.Id
AND B.OldId In (1,2)

Answer 6

试试这个

SELECT  name 
FROM tbCustomer tb1 
JOIN (SELECT ID FROM tbOldCustomer WHERE oldID = 1 OR oldID= 2) tb2
     ON tb1.ID = tb2.ID
WHERE tb1.ID IN (SELCT ID from tbOldCustomer where oldID in (1, 2))