Using Stored Procedures/parameters When WHERE String Has Optional Conditions

I've created a search page in my asp.net app that allows the user to enter optional parameters to narrow down the result set. It looks something like:Find all parts where:   manuafacturer:    <dropdownlist>ANY | manufacturer 1 |... </dropdownlist>   model:               <dropdownlist>ANY | model 1 |... </dropdownlist>   cost:                  between <textbox> and <textbox> dollarsCurrently I create the SQL command on the fly building the WHERE based on what the user selects. For example if in the form above they select    manufacturer = manufacturer1   model = ANY   cost = between 10 and 15the WHERE string is    ... WHERE manufacturer='manufacturer1' AND cost BETWEEN 10 AND 15Since the user doesn't care about model I leave it out of the WHERE. OK so here is my question. I want to move my queries to strored procedures however I'm not sure how to create the query since it changes based on what the user enters. Using the example above I'm assuming I can create one query with 4 parameters however what value would I use for ANY?    parameter1 (manufacturer) = "manufacturer1"   parameter2 (model)  = ???   parameter3 (price low) = 10   parameter4 (proce high) = 15I see there is an ANY operator in T-SQL but it doesn't look like the right thing to use. Should I use LIKE '%'? Seems that using LIKE would result in addition overhead.ThanksSimon