I'm getting a frustrating error in one of my SQL Server 2008 queries. It parses fine, but crashes when I try to execute. The error I get is the following: Msg 8120, Level 16, State 1, Line 4 Column 'customertraffic_return.company' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause. SELECT * FROM (SELECT ctr.sp_id AS spid, Substring(ctr.company, 1, 20) AS company, cci.email_address AS tech_email, CASE WHEN rating IS NULL THEN 'unknown' ELSE rating END AS rating FROM customer_contactinfo cci INNER JOIN customertraffic_return ctr ON ctr.sp_id = cci.sp_id WHERE cci.email_address <> '' AND cci.email_address NOT LIKE '%hotmail%' AND cci.email_address IS NOT NULL AND ( region LIKE 'Europe%' OR region LIKE 'Asia%' ) AND SERVICE IN ( '1', '2' ) AND ( rating IN ( 'Premiere', 'Standard', 'unknown' ) OR rating IS NULL ) AND msgcount >= 5000 GROUP BY ctr.sp_id, cci.email_address) AS a WHERE spid NOT IN (SELECT spid FROM customer_exclude) GROUP BY spid, tech_email