MySQL hiba

Hiba az alábbi parancs végrehajtása közben:
SELECT name FROM galleries WHERE blog_id = AND gallery_id = 0

1064: 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 gallery_id = 0' at line 1

/www/blog/classes/db.class.php, 52. sor