I created a Custom Parser for my log file and it seems to work well, except when I try to add a SQL filter.  It never returns any results if I try to use a custom column in the WHERE clause.  The custom column does show up in the "Available Columns" tab when I'm editing the filter, but when I click on the "Execution Result" tab, I get a warning that says, "No data found for field '<CustomFieldName>'". The "Test" button tells me that the SQL statemen parsed correctly.

What am I missing?