Question

大家好我一直在尝试做这个SQL，但它显示了这条消息。我不知道为什么因为条件有一个IN来搜索子查询，但是卡在它上面。

查询

SELECT PRO.ID_PRODUCTO,
PRO.ID_CATEGORIA,
PRO.DESCRIPCION AS DESCRIPCION
FROM T_PRODUCTO PRO  WHERE PRO.ID_CATEGORIA in (
      CASE WHEN @ID_CATEGORIA = '0' 
      THEN PRO.ID_CATEGORIA 
      ELSE 
      (Select [Data] 
      from dbo.fnSplit('1,3,4,5',',')
      )

消息

Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.

Answer 1

SELECT  PRO.ID_PRODUCTO,
        PRO.ID_CATEGORIA,
        PRO.DESCRIPCION AS DESCRIPCION
FROM T_PRODUCTO PRO  
WHERE @ID_CATEGORIA = '0' 
OR PRO.ID_CATEGORIA IN (SELECT [Data] 
                        FROM dbo.fnSplit('1,3,4,5',','))

Answer 2

在CASE语句中使用时，子查询将被计算为表达式。

您可以以不同的方式应用案例陈述（因为它基于您的@ID_CATEGORIA变量）：

SELECT PRO.ID_PRODUCTO,
PRO.ID_CATEGORIA,
PRO.DESCRIPCION AS DESCRIPCION
FROM T_PRODUCTO PRO  WHERE
(
  @ID_CATEGORIA <> '0' 
  AND PRO.ID_CATEGORIA IN ( 
    SELECT [Data] FROM dbo.fnSplit('1,3,4,5',',')
  )
)
OR
(
  @ID_CATEGORIA = '0'
  AND PRO.ID_CATEGORIA = PRO.ID_CATEGORIA
)

子查询在条件内返回了多于1的值

2 个答案: