sql where 구문만들기

$where = array();
if(! empty($field))
{
    $where[] = " field < ".$field. "";
}

$sql = "SELECT * FROM table " ;

if(count($where))
{
    $sql .= " WHERE ".implode( " AND ", $where);
}

방식2

$where[] = array( "field" => "aaaa",
                                "value" => "%aaaa%",
                                "compare" => "LIKE");