Database Error; SQL: SELECT DISTINCT `t`.* FROM `wp_posts` AS `t` WHERE ( ( `nivel_educacion`.`slug` LIKE '' ) AND ( `t`.`post_type` = 'novedad' ) AND ( `t`.`post_status` IN ( 'publish' ) ) ) ORDER BY `t`.`post_date` ASC, `t`.`menu_order`, `t`.`post_title`, `t`.`post_date` LIMIT 0, 4; Response: Unknown column 'nivel_educacion.slug' in 'where clause'