Mysql 在WHERE子句中使用子查询结果列时出现未知列

我加入了几个表，使用

COUNT（）

为总计选择一列。此查询在返回

total

列时非常有效：

SELECT *,`excel`.`drivers`.`AutoNumber` AS `current_driver`,
(SELECT COUNT(`issues`.`categories`.`points`) FROM `issues`.`points` INNER JOIN `excel`.`drivers` ON `issues`.`points`.`driver_id` = `excel`.`drivers`.`AutoNumber` INNER JOIN `issues`.`categories` ON `issues`.`categories`.`id` = `issues`.`points`.`category_id` WHERE `excel`.`drivers`.`AutoNumber`=`current_driver`) AS `total` 
FROM `issues`.`points` 
INNER JOIN `excel`.`drivers` ON `issues`.`points`.`driver_id` = `excel`.`drivers`.`AutoNumber` 
INNER JOIN `issues`.`categories` ON `issues`.`categories`.`id` = `issues`.`points`.`category_id`

但现在我尝试创建一个查询，比较WHERE子句中的

total

，如下所示：

SELECT *,`excel`.`drivers`.`AutoNumber` AS `current_driver`,
(SELECT COUNT(`issues`.`categories`.`points`) FROM `issues`.`points` INNER JOIN `excel`.`drivers` ON `issues`.`points`.`driver_id` = `excel`.`drivers`.`AutoNumber` INNER JOIN `issues`.`categories` ON `issues`.`categories`.`id` = `issues`.`points`.`category_id` WHERE `excel`.`drivers`.`AutoNumber`=`current_driver`) AS `total` 
FROM `issues`.`points` 
INNER JOIN `excel`.`drivers` ON `issues`.`points`.`driver_id` = `excel`.`drivers`.`AutoNumber` 
INNER JOIN `issues`.`categories` ON `issues`.`categories`.`id` = `issues`.`points`.`category_id` WHERE `total` = 3

---

这将返回一个错误，

total

是未知列。有什么想法吗？

列别名不能用在

WHERE

子句中。试一试

select a.* 
FROM 
(
SELECT [column_list]
,`excel`.`drivers`.`AutoNumber` AS `current_driver`,
(SELECT COUNT(`issues`.`categories`.`points`) FROM `issues`.`points` INNER JOIN `excel`.`drivers` ON `issues`.`points`.`driver_id` = `excel`.`drivers`.`AutoNumber` INNER JOIN `issues`.`categories` ON `issues`.`categories`.`id` = `issues`.`points`.`category_id` WHERE `excel`.`drivers`.`AutoNumber`=`current_driver`) AS `total` 
FROM `issues`.`points` 
INNER JOIN `excel`.`drivers` ON `issues`.`points`.`driver_id` = `excel`.`drivers`.`AutoNumber` 
INNER JOIN `issues`.`categories` ON `issues`.`categories`.`id` = `issues`.`points`.`category_id`
)a 
WHERE a.`total` >3

---

您也可以在

中重复“total”的整个定义，其中

-智能优化器很可能会生成相同的计划，但出于可读性考虑，我不会这样做。

完美。现在我对使用列别名有了更好的了解，谢谢！