GSquared: Thanks for helping me out.

I think some people are missing the point. Assuming is indexed, cast( as anything) will mean that 's index will never be used thus resulting in a table/index scan.

It's just like converting a datetime to a string. dateTimeKey's index is useless for selectivity if it's converted like so:

select ... from

T where convert(char(8),T.dateTimeKey,12) = "080107"

So searching with '%'+ cast( as varchar) + '%' is bad. It works fine for small tables because even bad SQL runs acceptably on small tables.