I have a search page with three dropdownlist controls and a search button. A simple select query to retrieve data in a datalist control is on the same web page. I like to filter data based on the three dropdownlist controls. In the filter column of my query I put a variable like this @controlname. One of the dropdownlist controls does not require input. If I put a variable for the field in the query I get an error message "...expects the parameter @controlname, which was not supplied". I have tried isnull(@controlname) did not work. How can I execute the query if no input in this particular control then show alle records based on the other control variables?