Question

假设我有查询：

SELECT Foo FROM Bar

返回

富
A
B
C

我到底是什么：
的富
A，B，C

因此，所有行中的所有值都已折叠为一行（逗号是可选的）。
有没有办法使用select语句来执行此操作，因为我不想使用游标？

Answer 1

DECLARE @foos VARCHAR(4000)

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

SELECT @foos AS Foo

Answer 2

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 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

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

尝试查看this answer。

它做了类似你想要做的事情。

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

如何将多行中的所有值合并为一行？

6 个答案: