The other aspect to be aware is that NULL + 'hello world' = NULL in SQL 7 on wards without ansi nulls off
Simon Sabin
Co-author of SQL Server 2000 XML Distilled
http://www.amazon.co.uk/exec/obidos/ASIN/1904347088
Simon Sabin
SQL Server MVP
http://sqlblogcasts.com/blogs/simons