mysql中使用update修改表中的数据

更新表中指定的数据

mysql> select * from dept1;
+--------+------------+----------+
| DEPTNO | DNAME      | LOC      |
+--------+------------+----------+
|     10 | ACCOUNTING | NEW YORK |
|     20 | RESEARCH   | DALLAS   |
|     30 | SALES      | CHICAGO  |
|     40 | OPERATIONS | BOSTON   |
|     10 | ACCOUNTING | NEW YORK |
|     20 | RESEARCH   | DALLAS   |
|     30 | SALES      | CHICAGO  |
|     40 | OPERATIONS | BOSTON   |
+--------+------------+----------+
8 rows in set (0.00 sec)

mysql> update dept1 set loc = 'SHANGHAI',dname = 'SALES' where deptno = 10;
Query OK, 2 rows affected (0.00 sec)
Rows matched: 2  Changed: 2  Warnings: 0

mysql> select * from dept1;
+--------+------------+----------+
| DEPTNO | DNAME      | LOC      |
+--------+------------+----------+
|     10 | SALES      | SHANGHAI |
|     20 | RESEARCH   | DALLAS   |
|     30 | SALES      | CHICAGO  |
|     40 | OPERATIONS | BOSTON   |
|     10 | SALES      | SHANGHAI |
|     20 | RESEARCH   | DALLAS   |
|     30 | SALES      | CHICAGO  |
|     40 | OPERATIONS | BOSTON   |
+--------+------------+----------+

更新表中所有的数据

mysql> update dept1 set loc = 'y',dname = 'x';
Query OK, 8 rows affected (0.00 sec)
Rows matched: 8  Changed: 8  Warnings: 0

mysql> select * from dept1;
+--------+-------+------+
| DEPTNO | DNAME | LOC  |
+--------+-------+------+
|     10 | x     | y    |
|     20 | x     | y    |
|     30 | x     | y    |
|     40 | x     | y    |
|     10 | x     | y    |
|     20 | x     | y    |
|     30 | x     | y    |
|     40 | x     | y    |
+--------+-------+------+
8 rows in set (0.00 sec)