Grouping in scripted calculation view

Hello,

I have a small doubt in the scripted calculation view.Let's say if i have to pick up fields from two tables. For simiplification , let's assume few fields alone.

TEMP1 = Select field1,field2 sum(field3) from table a group by field1;

TEMP2 = select field1,field4 sum(field5) from table b group by field3;

Now, when we call the VAR_OUT i need to join TEMP1 & TEMP2 to get the fields in a single join but VAR_OUT by default groups the dimensions i.e if i look at the generated code in data preview it is :

select field1, field2,field4,sum(field3), sum(field5) group by  field1,field2,field4;

So, my question is it mandatory to again say SUM(Measures) group by (dimensions) in the VAR_OUT or is it best if we just map the fields and the grouping will happen  automatically.

Regards,

Prem