What kinds of patterns you want to search for?

If not complex then you can use some expressions with LIKE clause.

Like if you want to search Canada ZIP codes, which are in following format 'X0X0X0', so for this you can use following query:

WHERE column_name LIKE '[a-zA-Z][0-9][a-zA-Z][0-9][a-zA-Z][0-9]'

Otherwise, like as other said, for complex searches you need CLR.