It's not SQL Server. vBulletin uses MySQL. So, given the version, this is MySQL 5.1.54 (still pretty outdated)
This isn't exactly T-SQL afterall - IF(votenum >= 1, votenum, 0) AS votenum,
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