Uncaught Exception: SqlException

Message:
invalid query:SELECT city_id,city_name from city where city_id=index 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 'index' at line 1
Created in file /var/www/vhosts/zeelists.com/httpdocs/usol/lib/database/SqlDatabaseManager.class.php on line 141.

Stack Trace:
#0 /var/www/vhosts/zeelists.com/httpdocs/protected/appcode/datamanager/HomeDataManager.php(168): SqlDatabaseManager->executeQuery('SELECT city_id,...')
#1 /var/www/vhosts/zeelists.com/httpdocs/protected/pages/forum.php(188): HomeDataManager->getCityName('index')
#2 [internal function]: forum->posts('143', '20', 'index')
#3 /var/www/vhosts/zeelists.com/httpdocs/usol/lib/RegisterCallback.class.php(8): call_user_func_array(Array, Array)
#4 /var/www/vhosts/zeelists.com/httpdocs/usol/lib/Application.class.php(47): RegisterCallback::register(Object(forum), 'posts', Array)
#5 /var/www/vhosts/zeelists.com/httpdocs/index.php(12): Application::run(Object(HttpRequest))
#6 {main}
5.
In file /var/www/vhosts/zeelists.com/httpdocs/protected/appcode/datamanager/HomeDataManager.php line 168.
Method: SqlDatabaseManager->executeQuery([$query FILTERED])
4.
In file /var/www/vhosts/zeelists.com/httpdocs/protected/pages/forum.php line 188.
Method: HomeDataManager->getCityName([$id FILTERED])
3.
In file unknown line unknown.
Method: forum->posts([$threadId FILTERED], [$topicId FILTERED], [$city_id FILTERED])
2.
In file /var/www/vhosts/zeelists.com/httpdocs/usol/lib/RegisterCallback.class.php line 8.
Method: call_user_func_array([$function_name FILTERED], [$parameters FILTERED])
1.
In file /var/www/vhosts/zeelists.com/httpdocs/usol/lib/Application.class.php line 47.
Method: RegisterCallback::register([$class FILTERED], [$funcName FILTERED], [$args FILTERED])
0.
In file /var/www/vhosts/zeelists.com/httpdocs/index.php line 12.
Method: Application::run([$request FILTERED])