MySQL存储过程中的if语句

Question

我在MySQL中有以下存储过程：

SELECT *
    FROM rewards
        LEFT JOIN tasks
        ON tasks.id = rewards.task_id
        AND rewards.received_at = received_Date
    WHERE tasks.kid_id = kid_Id
    ORDER BY tasks.id ASC;

该存储过程有2个(IN)输入: kid_Id (整数) 和 received_Date (日期)，目前它的运行良好。

问题: 我想要的是，如果received_Date为NULL，那么我希望能查看所有日期，这是否可能？

换句话说：

只有在传递received_Date时，AND rewards.received_at = received_Date才会起作用，否则将返回所有日期。

- Maytham Fahmi

Answer 1

尝试这个。在where子句中使用OR运算符，以便在received_Date为空时获取所有行。

SELECT *
    FROM rewards
        LEFT JOIN tasks
        ON tasks.id = rewards.task_id
                WHERE tasks.kid_id = kid_Id 
                AND (rewards.received_at = received_Date or received_Date = 0) 
    ORDER BY tasks.id ASC;

- Pரதீப்