使用内部联接时求和的条件？

Question

我有两个表：

a
idA User Size 
b
idB status name

User是从a到b的外键。

该查询运行良好：

SELECT a.User,a.size,b.status,b.name, SUM(a.size) as TotalSize
FROM a
LEFT OUTER JOIN b
ON a.User=b.idB
WHERE a.size> 10
GROUP BY User
ORDER BY TotalSize DESC

但是当我尝试对总和输入条件时，它失败了：

SELECT a.User,a.size,b.status,b.name, SUM(a.size) as TotalSize
FROM a
LEFT OUTER JOIN b
ON a.User=b.idB
WHERE TotalSize > 10  # or WHERE SUM(a.size)  > 10
GROUP BY User
ORDER BY TotalSize DESC

我该怎么办？

Answer 1

使用having子句（在group by后面）：

HAVING TotalSize > 10  # or HAVING SUM(a.size)  > 10

这是从聚合函数中过滤结果的正确方法。