er_clause is as described in\nhttps://dev.mysql.com/doc/refman/8.0/en/window-functions-usage.html; it\ncannot be used with DISTINCT.\n\nURL: https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html\n\n','mysql> SELECT student_name, AVG(test_score)\n       FROM student\n       GROUP BY student_name;\n','https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html');