I'm running a very simple query that I think should work. The only thing that I haven't done before is put a php variable in the WHERE clause of the query. The variable $X is a numerical value, say 100. When I run this query, I just get a value of 0 returned. Am I doing something obviously stupid? SELECT generator_64k.n FROM generator_64k WHERE generator_64k.n<= '$X' I've looked around the web and also tried this: SELECT generator_64k.n FROM generator_64k WHERE generator_64k.n<= '" . $X . "' But this also just returns 0. Any ideas? Thanks in advance.