GROUP BY using parameters in SQL

Question

I am trying to somehow group a report based on a drop-down list of parameters that is pre-defined. I want to be able to subtotal the Total Hours or Total Pay of my report b

Answer 1

Any column you are selecting that are not used by one of the aggregate function (SUM, MIN, etc) needs to be listed in the GROUP BY clause.

For example,

SELECT EmployeeID, LastName, FirstName, SUM(Hours) as "Total Hours"
FROM Employees
GROUP BY EmployeeID, LastName, FirstName

Good examples here: http://www.w3schools.com/sql/sql_groupby.asp