$sql = "SELECT title,created,work_company,
            IF(count(city_id) > 1,'Multiple cities',city.city_name) as city,
          IF(job_type =1,'Full time','Part time') as Job_type
                    FROM work_history
                  JOIN content ON content.owned_user = work_history.user_id
                  JOIN job ON content.content_id = job.content_id
          join job_city ON content.content_id = job_city.content_id
          JOIN city ON city.id = job_city.city_id
                    WHERE content.type =6 AND work_history. current_working = 1";
          if(!empty($filters['cataegory'])){
                       $sql .=" AND job.category = ".$filters['cataegory']."";
                    }
                    if(!empty($filters['type'])){
                       $sql .=" AND job.job_type = ".$filters['type']."";
                    }
                    if(!empty($filters['city'])){
                       $sql .=" AND city.id = ".$filters['city']."";
                    }
                    if(!empty($filters['min_salary'])){
                       $sql .=" AND job.min_sallary >= ".$filters['min_salary']."";
                    }