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;

存储过程有2个（IN）输入，kid_Id（整数）和received_Date（日期），并且工作正常。

问题：我想要的是，如果received_Date是NULL，那么我想查看所有日期，这可能吗？

换句话说：

AND rewards.received_at = received_Date仅在我通过received_Date时才有效，否则返回所有日期。

Answer 1

试试这个。如果OR

，请使用where clause中的received_Date is null运算符获取所有行

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;

带有if语句的MySQL存储过程

1 个答案: