DELETE FROM tbl_name [WHERE where_condition]
mysql> SELECT * FROM users;
+----+----------+----------+-----+------+
| id | username | password | age | sex |
+----+----------+----------+-----+------+
| 1 | Tom | 123 | 29 | 0 |
| 2 | John | 456 | 38 | 0 |
| 3 | Tom | 123 | 27 | 0 |
| 4 | John | 456 | 27 | 0 |
| | John | 456 | 10 | 0 |
| 10 | John | 456 | 21 | 0 |
| 11 | ROSE | 67 | 4 | 0 |
| 12 | Ben | 456 | 13 | 0 |
+----+----------+----------+-----+------+
mysql> DELETE FROM users WHERE id = 5;
Query OK, 1 row affected (0.04 sec)
mysql> SELECT * FROM users;
+----+----------+----------+-----+------+
| id | username | password | age | sex |
+----+----------+----------+-----+------+
| 1 | Tom | 123 | 29 | 0 |
| 2 | John | 456 | 38 | 0 |
| 3 | Tom | 123 | 27 | 0 |
| 4 | John | 456 | 27 | 0 |
| 10 | John | 456 | 21 | 0 |
| 11 | ROSE | 67 | 4 | 0 |
| 12 | Ben | 456 | 13 | 0 |
+----+----------+----------+-----+------+