Very good article. Stuff like this is always well worth keeping in mind. especially seeing as sybase and (if memory serves) oracle behave in the same way

nice one

here's one way to solve the problem posed by soln. number two

and isnull(ColumnOne, '%') like @pSearchArg

to use other operators (=, > etc.) try something like

and ColumnOne = insnull(@pSearchArg, ColumnOne)

the optimiser...