use of sql aggregate functions

Hi,

Yes you can use, but you supposed to put an group by clause for other than Aggregate function columns.

e.g.

Select o_id,SUM(qty) From table1
GROUP BY o_id

this will work and gives you sum of qty and output is equal to 1 row only.

Regards,
V.J.

it is simple in group by give the column name on which you want to grouping

when you use this query

select o_id,sum(qty) from table1

it will return error
now you can write this query like that:-

select o_id,sum(qty) from table1 group by o_id

then it will not return error and give result of sum is:- either 192 or 496 is it correct.

if you want sum of 192 and 496 then you can write it as :-

select sum(qty) from table1 

then it will return 688.

If you run above query then It will throw below error

Msg 8120, Level 16, State 1, Line 10
Column 'table1.o_id 39; is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.

And to resolve this we need to add Group by clause like below

select o_id,sum(qty) from table1 GROUP BY o_id

Final result would be

o_id	qty
a196	688

Hope this helps , If yes then plz accept and vote the answer. Any queries / questions on this are always welcome.

Thanks & Regards
RDBurmon.Sr.Software Engineer