user deletion correct

$query->( "
DELETE
    U, SB, S, O
FROM
    users AS U
LEFT JOIN
    shopping_bag AS SB
ON
    SB.id = U.id
LEFT JOIN
    settings AS S
ON
    S.id = SB.id
LEFT JOIN
    orders AS O
ON
    O.id = S.id
WHERE
    U.id = " . MySQLiDatabase::getInstance()->escapeValue( getPost( 'selected_user' ) ) . "
" );