MySQL, PHP help wanted

I am quite a beginner to MySQL. I have this simple expression which I need to filter.

$a = "2";    
$s1 = sprintf("%s,",$a)."%";
$s2 = "%".sprintf(",%s,",$a)."%";
$s3 = "%".sprintf(",%s",$a);


$res = mysql_query("SELECT busno FROM busroute WHERE route LIKE '$s1' OR route LIKE '$s2' OR route LIKE '$s3' ");
// This basically searches for "2," OR ",2," OR ",2" in route.

If I use the exact same expression in MySQL browser, I get my results. But it simply returns null in PHP. Help! I know I am missing something, but cant figure out what开发者_C百科.

mysql_query's documentation says:

For SELECT, SHOW, DESCRIBE, EXPLAIN and other statements returning resultset, mysql_query() returns a resource on success, or FALSE on error.

You also have to retrieve the results:

while(($row = mysql_fetch_array($res))) {
    print_r($row);
}

Have a look at the documentation for more examples and information.

Update:

Because this solved the problem: Use mysql_error to find out the problem with the query.

If it's not just a typo, take a look at this bit: s2'. It should be '$s2'. Also, PHP should be fine with this string. Have a look at the data in the table.