mysql - 如果条件列为真则添加值

Question

我有一个如下所示的 MySql 查询:

SELECT o.id, 
       o.priorytet_1 + 
       o.priorytet_2 +
       o.priorytet_3 AS bonus 
FROM obiekty o 
WHERE o.ac=1 
GROUP BY o.id 
ORDER BY `o`.`id` ASC 

在 priorytet_1, priorytet_2 and priorytet_3 旁边我有的专栏priorytet_1_valid, priorytet_2_valid, priorytet_3_valid我存储日期的位置，例如 priorytet_1已验证。

我只想添加那些日期为 < now() 的列。

类似于:

SELECT o.id, 
       if (o.priorytet_1_valid < now()) o.priorytet_1 + 
       if (o.priorytet_2_valid < now()) o.priorytet_2 + 
       if (o.priorytet_3_valid < now()) o.priorytet_3 AS bonus 
FROM obiekty o 
WHERE o.ac=1 
GROUP BY o.id 
ORDER BY `o`.`id` ASC

感谢您的帮助!

Answer 1

尝试:

SELECT o.id, 
       SUM(IF (o.priorytet_1_valid < NOW(), o.priorytet_1, 0) + 
           IF (o.priorytet_2_valid < NOW(), o.priorytet_2, 0) + 
           IF (o.priorytet_3_valid < NOW(), o.priorytet_3, 0)) AS bonus
FROM obiekty o 
WHERE o.ac=1 
GROUP BY o.id 
ORDER BY `o`.`id` ASC

您可能想要使用 SUM，因为您有一个 GROUP BY 子句。上述查询中使用的 SUM 函数有条件添加字段 o.priorytet_1、o.priorytet_2、o.priorytet_3，以防相应的“有效”字段早于当前日期/时间。