Can Multiple Columns Be Used in GROUP BY in SQL Server?

If you want to break your output into smaller groups, you can specify multiple column names or expressions in the GROUP BY clause. Output in each group must satisfy a specific combination of the expressions listed in the GROUP BY clause. The more columns or expressions entered in the GROUP BY clause, the smaller the groups will be.

The tutorial exercise below shows you how to break data into groups per "tag" and per year when they were created. Then the group function COUNT(*) is applied on each group:

SELECT tag, YEAR(created), COUNT(*) 
   FROM fyi_links GROUP BY tag, YEAR(created)
GO
tag     year(created)   count(*)
SQA     2003            1
DEV     2004            1
DBA     2005            1
DBA     2006            1
DEV     2006            1
DBA     2007            1
SQA     2007            1

So there is only one row in each group.

⇒ Using Group Functions in the ORDER BY Clause in SQL Server

⇐ How To Count Duplicated Values in a Column? in SQL Server

⇑ Using SELECT Statements and GROUP BY Clauses in SQL Server

⇑⇑ SQL Server Database Tutorials