A function like is_page() but returns true if on any sub page of given page

When using pretty permalinks, I simply check against the request;

if ( preg_match( '#^stores(/.+)?$#', $wp->request ) ) {
    // away we go!
} 

No extra DB queries, little computation, and works right down the tree!

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)