Only if all other columns are part of aggregate expressions. The query you have there is not valid. This would be.
SELECT col1, max(col2), Max(col3)
FROM TableA
GROUP BY col1
Think about it. You're asking for 1 row for each value that's in Col1 (that's what group by means). SQL has to know what to do with the multiple values of col2 and col3.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability