帮我看看这条SQL语句是什么意思？内容看正文
SELECT CASE WHEN EXISTS (SELECT * FROM dbo.tbRevisionSupersedesUpdate AS S WHERE S.SupersededUpdateID=Up.UpdateID) THEN CAST (1 AS BIT) ELSE CAST(0 AS BIT) END AS IsSuperseded)

[解决办法]
SELECT * FROM dbo.tbRevisionSupersedesUpdate AS S WHERE S.SupersededUpdateID=Up.UpdateID


---如果这个语句查询有记录就返回1，否则返回0
[解决办法]
SELECT CASE WHEN
EXISTS (SELECT * FROM dbo.tbRevisionSupersedesUpdate AS S WHERE S.SupersededUpdateID=Up.UpdateID)
THEN CAST (1 AS BIT)
ELSE CAST(0 AS BIT) END
AS IsSuperseded--去掉这个)

exists为判断真假


[解决办法]
end是case语句的结束,AS IsSuperseded 列别名