テーブルに格納されているカラムのデータをすべて空にする

mysql> delete from テーブル名;

mysql> select * from test_table;
+-------------+---------+----------+----------+
| response_id | user_id | topic_id | response |
+-------------+---------+----------+----------+
|           1 |       2 |        3 |        2 |
|           2 |       1 |        3 |        5 |
+-------------+---------+----------+----------+
2 rows in set (0.00 sec)

mysql> delete from test_table;
Query OK, 2 rows affected (0.01 sec)

mysql> select * from test_table;
Empty set (0.00 sec)

mysql>