使用PIVOT函数时，IN子句中的值必须与您选择的值匹配.您当前的数据不包括1、2或3.您可以使用row_number()为每个x分配一个值:

When you are using the PIVOT function the values inside the IN clause need to match a value that you are selecting. Your current data does not include 1, 2, or 3. You can use row_number() to assign a value for each x:

select x, [1], [2], [3]
from
(
  select x, value,
    row_number() over(partition by x order by y) rn
  from test
) d
pivot
(
  max(value)
  for rn in ([1], [2], [3])
) piv;

请参见带演示的SQL提琴.如果每个x的值数量未知，那么您将要使用动态SQL:

See SQL Fiddle with Demo. If you then have a unknown number of values for each x, then you will want to use dynamic SQL:

DECLARE @cols AS NVARCHAR(MAX),
    @query  AS NVARCHAR(MAX)

select @cols = STUFF((SELECT distinct ',' + QUOTENAME(row_number() over(partition by x order by y)) 
                    from test
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,1,'')

set @query = 'SELECT x,' + @cols + ' 
            from 
            (
              select x, value,
                row_number() over(partition by x order by y) rn
              from test
            ) x
            pivot 
            (
                max(value)
                for rn in (' + @cols + ')
            ) p '

execute(@query);

请参见带有演示的SQL提琴