Requete SQL

Bonjour,

j' ai une requete ki marchais tres bien mais lorske je concatène avec ($query .= " ORDER BY id DESC LIMIT ".$premiereEntree.", ".$messagesParPage."";) il ne répond plus,
et-il possible de faire un fonction? si oui comment:

$query = "SELECT * FROM jos_ezautos WHERE make='" . $A . "' AND model='" . $b . "'";
if( $d != -1 ){
$query .= " AND fuel LIKE'$d%'"; // si le carburant different de 0
}
if( $f != -1 ){
$query .= " AND price>=" . $f; //si prix mini diff de -1
}
if( $g != -1 ){
$query .= " AND price<=" . $g; //si prix max diff de -1
}
//$query .= " AND prix BETWEEN(" . $f . " AND " . $g . ")";
if( $e != -1 ){
$query .= " AND year>=" . $e; //si anne mini diff de -1
}
if( $h != -1 ){
$query .= " AND year<=" . $h; //si anne max diff de -1
}
if( $c != -1 ){
$query .= " AND mileage>=" . $c; //si kilo mini diff de -1
}
if( $i != -1 ){
$query .= " AND mileage<=" . $i; //si kilo max diff de -1
$query .= " ORDER BY id DESC LIMIT ".$premiereEntree.", ".$messagesParPage."";
}
$retour_messages = mysql_query( $query ) or die( "Echec de selection" );

while($donnees_messages=mysql_fetch_assoc($retour_messages)
{