PHP and MySQL optional WHERE conditions

Question

I have the following problem: I want to let a user apply filters to a DB search. I have three filters, A, B and C. All of them can be \"empty\", as in, the user doesn\'t care a

Answer 1

The other answers are mostly correct, but this is a simpler way to accomplish what is needed:

$where = array();


if($A != 'any'){ // or whatever you need
    $where[] = "A = $A'";
}
if($B != 'any'){ // or whatever you need
    $where[] = "B = $B'";
}
if($C != 'any'){ // or whatever you need
    $where[] = "C = $C'";
}

$where_string = implode(' AND ' , $where);

$query = "SELECT * FROM table";

if($where){
    $query .= ' ' . $where_string;
}

This will allow for any combination of conditions and expansion.