Question

I have a table which looks like this:

Name   |   Quantity  |   Unit
-------+-------------+----------
Water         10        Lt
Water         5         Lt
Water         3         Lt
Snacks        20        Kg
Snacks        15        Kg
Beer          7         Lt
Beer          12        Lt
Pizza         1         Piece
Pizza         2         Piece
Pizza         5         Piece

I need to get these results:

Name   |  Quantity_Unit  
-------+------------------
Water         18 Lt
Snacks        35 Kg
Beer          19 Lt
Pizza         8 Piece

So I need to select sum of quantities by products AND add unit of measure in the same column. It is pretty simple and that’s how I do it:

select name, cast(sum(quantity) as nvarchar) + ' ' + max(unit) as total 
from goods group by name

My question is how can I add units of measure to aggregated column with sum(quantity) not using aggregate functions like max(unit) or using max() is fine for this case? Basically all goods in group by will have the same unit of measure and I’m looking for most elegant query. Thanks.

Answer 1

In your case, you can either use MAX or MIN and it would not make any difference for your result.

You can also avoid the aggregate functions MAX and MIN by just querying column unit and adding the same in group by clause as well.

select name, cast(sum(quantity) as nvarchar) + ' ' + unit as total 
from goods group by name, unit