mysql - MySQL的加入与左联接和分组依据

我想结合三个sql查询，查询如下，site和goods列是普通列，我要在我的结果中有9列，如果您一一运行这三个查询，您将得到3个结果有3列，我想要结合这三个结果

select distinct
  a.site,a.goods,
  sum(a.quantity)
from
  stock_consumed a
group by
  a.site,a.goods


select distinct
  b.site,
  b.goods,sum(b.quantity)
from
  opening_balance b
group by
  b.site,b.goods


select distinct
  c.site,
  c.goods,sum(c.no_of_units)
from
  inward_stock c
group by
  c.site,c.goods

最佳答案

您正在寻找union。它允许您组合两个查询的结果，只要它们的结果具有相同的列数即可。

select distinct a.site,a.goods,sum(a.quantity) from stock_consumed a group by a.site,a.goods
union
select distinct b.site,b.goods,sum(b.quantity) from opening_balance b group by b.site,b.goods
union
select distinct c.site,c.goods,sum(c.no_of_units) from inward_stock c group by c.site,c.goods

关于mysql - MySQL的加入与左联接和分组依据，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/28734951/