1. 单表更新：将表 t1 中 “t1.c1=1” 对应的那一行数据的 c2 列值修改为 100。
    1. obclient> UPDATE t1 SET t1.c2 = 100 WHERE t1.c1 = 1;
    2. Query OK, 1 row affected (0.02 sec)
    3. Rows matched: 1  Changed: 1  Warnings: 0
    5. +----+------+
    6. | c1 | c2   |
    7. +----+------+
    9. |  3 |    3 |
    10. |  4 |    4 |
    11. +----+------+