SQL条件AND子句

我想添加一个具有以下功能的条款：

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

这是我想要的逻辑

• 当@requiresprapproval=1时，则添加子句：AND approved=1
• 当@requiresprapproval=0时，则省略子句：和approved=1

我的目标是根据@RequireApproval的值，使SQL最终成为以下任意一种类型。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

---

嗯。这应该实现您的逻辑：

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

---

您可以使用此查询-您只需要在两个条件之间使用

或

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

这也可以奏效

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