You can use the Performance Dashboard 2005 for SQL Server 2008.

1. Time out : I thought your table need to Index tunning. If your Database version is 2005, I recommend that use the indexed view.

If you give more detail table...

SELECT entityid, COUNT(DISTINCT INVOICE) FROM [YOUR TABLE] GROUP BY entityid

Thank you.

SELECT entityid, COUNT(DISTINCT INVOICE) FROM [YOUR TABLE] GROUP BY entityid

It's answer is wrong!!

Select EmpName, DateOfLeaving from Employees order by DateOfLeaving desc, EmpName asc

This query returns descending Order of DateOfLeaving.

It is so clear!!

wrong answer.!!