title: I have a following mistake: PG::UndefinedColumn: ERROR: column students.year_course_id does not exist LINE 1
body: <p>Change my code! I have a following mistake: PG::UndefinedColumn: ERROR: column students.year_course_id does not exist LINE 1: SELECT COUNT(<em>) FROM "students" WHERE "students"."year_cour... ^ : SELECT COUNT(</em>) FROM "students" WHERE "students"."year_course_id" = $1</p>