Discuz! Database Error

(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 '' at line 1

SELECT count(*) as k FROM forum_post,forum_typeoptionvar WHERE forum_post.fid=36 and forum_post.first=1 and forum_typeoptionvar.tid=forum_post.tid and forum_typeoptionvar.optionid=13 and forum_typeoptionvar.value=

PHP Debug

No.	File	Line	Code
1	sample.php	84	discuz_database::result_first()
2	source/class/discuz/discuz_database.php	123	discuz_database::query()
3	source/class/discuz/discuz_database.php	142	db_driver_mysqli->query()
4	source/class/db/db_driver_mysqli.php	148	db_driver_mysqli->halt()
5	source/class/db/db_driver_mysqli.php	223	break()