Data types

Not all data types can be used with every group function. Let's try and see what calculations are possible with the eSymphony data. Below you'll find a table with the columns used in this exercise and some example values.

Column name	Example values
Milliseconds	343719, 205662, 342562
HireDate	2002-08-14, 2002-05-01, 2003-10-17
Total	1.98, 3.96, 5.94
FirstName	Helena, Astrid, Roberto
City	Copenhagen, New York, Brussels
UnitPrice	0.99, 1.99, 0.99
Country	Brazil, Austria, Germany
Composer	Jimmy Page, Frank Zappa, John Deacon

Your job is to figure out what group functions can be used on these columns.