error: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2) executing: select course_details.COURSE_ID, COURSE_NAME,course_members.USER_ID from course_details left join course_members on (course_details.COURSE_ID=course_members.COURSE_ID AND course_members.USER_ID = '') where (course_details.KA_ID = '122' and course_details.JOINABLE = '1' and course_details.COURSE_STATUS_ID > 1)