sql - 具有聚合函数的多个 mysql JOIN

Question

我正在尝试加入 3 张桌子

文章、库存和已售表

我想为每篇文章从表 Stock 中选择其 QteEntre 的总和，从表中选择 Qte 的总和 Sold here s my code

Select  Article.IdArt,
        Sum(sold.Qte),
        Sum(Stock.QteEntree)
from (((Article) 
        Left Join Sold on Sold.IdArt = Article.IdArt)
        Left Join Stock on Stock.IdArt = Article.IdArt)
Group by Article.IdArt

但我总是得到（例如）IdArt 乘以 2 的 QteEnttree 和乘以 3 的 Qte 的结果我猜是因为我在 Sold 表中有 2 条记录，在 Stock 表中有 3 条记录

我怎样才能解决这个问题？

谢谢

Answer 1

使用子查询试一试：

select a.IdArt,
       (select sum(Qte) from Sold where IdArt = a.IdArt group by IdArt) as QteSum,
       (select sum(QteEntree) from Stock where IdArt = a.IdArt group by IdArt) as QteEntreeSum
from Article a