topic Re: sql queries in QlikView

sql queries

Anonymous — Wed, 25 Nov 2020 16:16:04 GMT

i have 2 queries

select empid, ename, sal from emp group by empid;

select empid, ename, max(sal) from emp group by empid;

now which query executes correctly?

Re: sql queries

Gysbert_Wassenaar — Mon, 07 Aug 2017 11:07:26 GMT

Neither, unless you have an SQL DBMS that doesn't conform to standard sql.

Re: sql queries

chris_johnson — Mon, 07 Aug 2017 11:48:20 GMT

Hi,

The problem you have with both queries is if you are doing a "group by" statement in SQL you have to make sure that every field is either part of the "group by" or being aggregated (like "max" in your second statement).

So if you change the 2nd statement to be:

select empid, ename, max(sal) from emp group by empid, ename;

That should work!

Re: sql queries

sasiparupudi1 — Mon, 07 Aug 2017 17:17:57 GMT

Aggregation and group by goes together always.

1) select empid, ename, sal from emp group by empid;

This statement do not need a group by as there is no aggregation(sum/Max/Count etc) involved

2) select empid, ename, max(sal) from emp group by empid;

This statement is partially correct as group by is missing ename.Basically, group by clause should contain all the non aggregated fields

hth

Sasi