Issue
I'm trying to write an SQL query that combines two tables and two columns in one of the tables. So, I have two tables
Table: Items
ID Material Shape
1 glass jar
2 plastic bottle
3 cardboard box
4 glass bottle
Table: Diary
ItemID UserID Quantity
2 1 1
1 1 3
3 1 2
2 1 5
4 1 1
Expected output where UserID = 1
(sorted by combined quantity
):
Combined column values Combined quantity
plastic bottle 6
glass jar 3
cardboard box 2
glass bottle 1
Could someone direct me the right way?
Solution
I think this is just a join
and 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;
Answered By - Gordon Linoff
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