SQL Server存储过程返回：子查询返回的值超过1

Question

我收到一个错误，因为SELECT / CASE返回多行，我想。我想请求帮助，并学习如何将我的存储过程从基于单行的参数转换为无参数代码，并能够为多个记录运行存储过程。

整条信息显示：

  

子查询返回的值超过1。当子查询遵循=，！=，＆lt;，＆lt; =，＆gt;，＆gt; =或子查询用作表达式时，不允许这样做。

这是我的代码：

BEGIN

SET NOCOUNT ON;

DECLARE @Desc  NVARCHAR(MAX);
SET @DESC = 'Beginning of description ';
SET @Desc = @DESC+(
SELECT
  CASE
    WHEN LEFT([pd].[Title], 1) = '"'
    THEN CONCAT('"', REPLACE([pd].[Title], '"', ''), '"')
  END
FROM [dbo].[Data_Feed] [df]
INNER JOIN [dbo].[ProductData] [pd]
    ON [df].[sku] = [pd].[ProductID]
WHERE pd.ProductType IN (19, 20, 23, 26, 27));

SET @DESC = (
SELECT
  CASE
    WHEN [df].[show] IS NOT NULL
    THEN CONCAT(@DESC, ' from ', [df].[show])
    ELSE CASE
           WHEN [df].[primary_performer] IS NOT NULL
           THEN CONCAT([df].[primary_performer], ' ', @DESC)
           ELSE CASE
                  WHEN [df].[performer] IS NOT NULL
                  THEN CASE
                         WHEN LEN([df].[performer])-LEN(REPLACE([df].[performer], ';', '')) > 1
                         THEN CONCAT(@DESC, ' by ', REPLACE(STUFF([df].[performer], LEN([df].[performer])-CHARINDEX(';',REVERSE([df].[performer]))+1, 1, ' and '), ';', ', '))                                                                                              
                         ELSE CONCAT(@DESC, ' by ', REPLACE([df].[performer],';', ' and '))                                                                                      
                       END
                  ELSE CASE                                                                              
                         WHEN [df].[composer] IS NOT NULL
                         THEN CASE
                                WHEN LEN([df].[composer])-LEN(REPLACE([df].[composer], ';', '')) > 1
                                THEN CONCAT(@DESC, ' by ', REPLACE(STUFF([df].[composer], LEN([df].[composer])-CHARINDEX(';', REVERSE([df].[composer]))+1, 1, ' and '),';', ', '))                                                                                                      
                                ELSE CONCAT(@DESC, ' by ', REPLACE([df].[composer], ';', ' and '))
                              END
                       END
                END
         END
  END
FROM [Data_Feed] [df]);

SET @DESC = @DESC+(
SELECT
  CASE
    WHEN [df].[scoring] IS NULL
    THEN CONCAT(RTRIM(@DESC), '.')
    ELSE CASE
           WHEN CHARINDEX(';', [df].[scoring]) > 0
           THEN CONCAT(' in ', LEFT([df].[scoring], CHARINDEX(';', [df].[scoring], 1)-1), ' format.')
           ELSE CONCAT('  in ', [df].[scoring], ' format.')
         END
  END
FROM [Data_Feed] [df]);

UPDATE [Data_Feed]
SET
  [description] = @Desc         

END;