如何将多行中的所有值合并到一行中？

Question

可以说我有查询：

SELECT Foo FROM Bar 

它返回

富
一个
乙
Ç

我真正的是：
富
A，B，C

因此，所有行的所有值都被折叠为一行（逗号是可选的）。
有没有办法使用select语句来做到这一点，因为我不想使用游标？

Answer 1

SELECT 
    ( 
    SELECT 
     CASE 
     WHEN ROW_NUMBER() OVER(ORDER BY bar) = 1 THEN '' 
     ELSE ', ' 
     END + CAST(bar AS VARCHAR) 
    FROM foo 
    ORDER BY bar 
    FOR XML PATH('') 
    ) 

Answer 2

DECLARE @foos VARCHAR(4000) 

SELECT @foos = COALESCE(@foos + ',', '') + Foo FROM Bar 

SELECT @foos AS Foo 

Answer 3

罗斯，

这应该让你开始。

DECLARE @r VARCHAR(8000) 
    SELECT @r = (SELECT DISTINCT Foo + ', ' FROM Bar FOR XML PATH('')) 
    IF @r IS NOT NULL AND @r <> '' SET @r = SUBSTRING(@r, 1, LEN(@r)-1) 
    SELECT @r 

Answer 4

请尝试以下

declare @joined varchar(max) 
set @joined = '' 

select @joined = @joined + IsNull(Foo + ',', '') 
from Bar (nolock) 

--; Drop last "," if necessary 
set @joined = substring(@joined, 1, len(@joined) - (case when len(@joined) > 0 then 1 else 0 end)) 
select @joined as foo 

Answer 5

尝试看看this answer。

它做的事情就像你想做的事情。

Answer 6

select max(a),max(b),max(c) from 
(
     select 'a' as a,null as b,null as c 
     union 
     select null,'b',null 
     union 
     select null,null,'c' 
) as x