How to use group by in SQL Server query?

Question

I have problem with group by in SQL Server

I have this simple SQL statement:

select * 
from Factors 
group by moshtari_ID

and I get

Answer 1

If you are applying group clause then you can only use group columns and aggregate function in select

syntax:

SELECT expression1, expression2, ... expression_n, 
       aggregate_function (aggregate_expression)
FROM tables
[WHERE conditions]
GROUP BY expression1, expression2, ... expression_n
[ORDER BY expression [ ASC | DESC ]];