我正在尝试编写一个SQL查询,该查询将两个表和其中一个表中的两列组合在一起。所以,我有两个桌子
表格:Items
ID Material Shape
1 glass jar
2 plastic bottle
3 cardboard box
4 glass bottle
表格:Diary
ItemID UserID Quantity
2 1 1
1 1 3
3 1 2
2 1 5
4 1 1
预期的输出UserID = 1
(按combined quantity
排序):
Combined column values Combined quantity
plastic bottle 6
glass jar 3
cardboard box 2
glass bottle 1
有人可以指引我正确的方向吗?
答案 0 :(得分:0)
我认为这只是join
和group by
:
select concat_ws(' ', i.material, i.shape) as combined,
sum(d.quantity) as combined_quantity
from items i left join
diary d
on d.itemId = i.id
group by combined
order by combined_quantity desc;
答案 1 :(得分:0)