Question

我希望根据某些条件将AND条件附加到WHERE子句。以下是我面临的情况

DECLARE
    @param1 INT, @param2 INT

SET @param1 = 1
SET @param2 = 1

SELECT *
FROM Table1 t1
INNER JOIN Table2 t2 ON t1.a = t2.b
INNER JOIN TABLE Table3 t3 ON t3.c = t2.d
WHERE t1.id = 1
  AND t2.id = 2

这是我希望条件进入的地方 -

Case when `@param1 = 1` and `@param2 = 1` THEN `AND t3.id = 4`

但我想这并不是这样的吗？：/为此有任何解决方法吗？

Answer 1

只需将其添加到where子句

即可

and isnull(t3.id,'') = case when @param1 = 1 and @param2 = 1 then 4 else isnull(t3.id,'') end

Answer 2

我会把它写成：

where t1.id = 1 and t2.id = 2 and
      ((@param1 = 1 and @param2 = 1 and t3.id = 4) or
       not (@param1 = 1 and @param2 = 1)
      )

这确实假设参数不是NULL。

Answer 3

您可以将以下内容添加为AND条件，以检查t3.id = 4和@param1何时@param2等于1，或者如果他们没有其他条件别＆＃39; T：

SELECT *
FROM Table1 t1
INNER JOIN Table2 t2 ON t1.a = t2.b
INNER JOIN Table3 t3 ON t3.c = t2.d
WHERE 
    t1.id = 1
    AND t2.id = 2
And
(
    (
        @param1 = 1
    And @param2 = 1
    And t3.id = 4
    )
    Or
    (
        @param1 <> 1
    Or  @param2 <> 1
    )
)

在SQL Server中附加条件AND条件？

3 个答案: