Sql server 如何使用in操作符的用例

有如下查询：

declare @case int =  1

SELECT a.column1,b.column2
FROM tbl1 a
INNER JOIN tbl2 b on a.id = b.id and a.category in(1,2,3,4,5)

当

@case=1

类别必须在（1,2,3,4,5）中时需要，当

@case=2

类别必须在（1,2,4,5）中时需要。 大概是这样的：

 SELECT a.column1,b.column2
 FROM tbl1 a
 INNER JOIN tbl2 b on a.id = b.id and (CASE WHEN @case = 1 THEN a.category in(1,2,3,4,5) WHEN @case = 2 THEN (1,2,4,5) ELSE '')

怎么做

SELECT a.column1,b.column2
FROM tbl1 a
INNER JOIN tbl2 b on a.id = b.id 
                 and 
                 (
                     (@case = 1 and a.category in (1,2,3,4,5)) OR
                     (@case = 2 and a.category in (1,2,4,5))
                 ) 

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为了便于阅读，我添加了括号。并非所有这些都是必要的。

另一个答案更好，但如果你碰巧想用case来做，你可以像这样做

SELECT a.column1,b.column2
FROM tbl1 a
INNER JOIN tbl2 b on a.id = b.id and 
    (    CASE WHEN @case = 1 and a.category in(1,2,3,4,5) THEN 1
              WHEN @case = 2 and a.category in(1,2,3,4) THEN 1 
              ELSE 0
         END
    ) = 1