Cannot query the database.

select URLName, Name from elevations where modelid = and status = 'enabled' order by name

Error:
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'and status = 'enabled' order by name' at line 1
Trace: (database.class.php:113)
(data.class.php:140)
(main.class.php:230)
(default.class.php:70)
(default.class.php:38)
(default.class.php:278)
(main.class.php:861)
(manager.class.php:24)
(document.class.php:218)
(document.class.php:104)
(index.php:13)