Question

我想添加一个执行以下操作的子句：

DECLARE @RequiresApproval BIT
SET @RequiresApproval = 0
SELECT * FROM [user] u
WHERE school_id = 1

这是我想要的逻辑

当@RequiresApproval = 1时，然后添加子句：AND approved = 1
当@RequiresApproval = 0时，请忽略条款：AND approved = 1

我的目标是让SQL最终得到以下任何一种，具体取决于@RequiresApproval的值。这可能吗？

-- when @RequiresApproval = 1, use this
SELECT * FROM [user] u
WHERE school_id = 1


-- when @RequiresApproval = 0, use this
SELECT * FROM [user] u
WHERE school_id = 1
AND approved = 1

Answer 1

确定。这应该实现你的逻辑：

SELECT *
FROM [user] u
WHERE school_id = 1 AND
      (@RequiresApproval = 0 or approved = 1);

Answer 2

您可以使用此查询 - 您只需在两个条件之间使用OR。

SELECT * FROM [user] u
WHERE school_id = 1
AND (approved = 1 OR @RequiresApproval = 0)

Answer 3

这也可以。

SELECT  * FROM  [user] u
WHERE   [school_id] = 1 AND [approved] = 1 
AND     @RequiresApproval = 1
UNION 
SELECT  * FROM  [user] u 
WHERE   [school_id] = 1 AND @RequiresApproval = 0

SQL条件和子句

3 个答案: