mysql> create table t (t int primary key); 
Query OK, 0 rows affected (0.01 sec)

mysql> insert into t set t=1;
Query OK, 1 row affected (0.00 sec)

mysql> insert into t set t=2;
Query OK, 1 row affected (0.00 sec)

mysql> select * from t;
+---+
| t |
+---+
| 1 | 
| 2 | 
+---+
2 rows in set (0.00 sec)

mysql> update t set t=t+10;
Query OK, 2 rows affected (0.00 sec)
Rows matched: 2  Changed: 2  Warnings: 0

mysql> select * from t;
+----+
| t  |
+----+
| 11 | 
| 12 | 
+----+
2 rows in set (0.00 sec)