mysql> select * from tb;
+------+------+------+
| 姓名 | 课程 | 分数 |
+------+------+------+
| 张三 | 语文 |?? 74 |
| 张三 | 数学 |?? 83 |
| 张三 | 物理 |?? 93 |
| 李四 | 语文 |?? 74 |
| 李四 | 数学 |?? 84 |
| 李四 | 物理 |?? 94 |
+------+------+------+
6 rows in set (0.01 sec)
mysql> update tb set 分数=replace(分数,74,100);
Query OK, 2 rows affected (0.05 sec)
Rows matched: 6? Changed: 2? Warnings: 0
mysql> select * from tb;???????????????????????
+------+------+------+
| 姓名 | 课程 | 分数 |
+------+------+------+
|?张三 | 语文 |? 100?|
| 张三 | 数学 |?? 83 |
| 张三 | 物理 |?? 93 |
|?李四 | 语文 |? 100?|
| 李四 | 数学 |?? 84 |
| 李四 | 物理 |?? 94 |
+------+------+------+
6 rows in set (0.01 sec)
====================================================================
mysql> select * from gg;
+----+------+
| id | name |
+----+------+
|? 1 | a??? |
|? 2 | b??? |
|? 3 | c??? |
+----+------+
3 rows in set (0.00 sec)
mysql> insert ignore into gg values(3,'d');
Query OK, 0 rows affected (0.00 sec)
mysql> select * from gg;???????????????????
+----+------+
| id | name |
+----+------+
|? 1 | a??? |
|? 2 | b??? |
|? 3 | c??? |
+----+------+
3 rows in set (0.00 sec)
mysql>
====================================================================
mysql> select * from gg;???????????????????
+----+------+
| id | name |
+----+------+
|? 1 | a??? |
|? 2 | b??? |
|? 3 | c??? |
+----+------+
3 rows in set (0.00 sec)
mysql> insert into gg values(3,'d') ON DUPLICATE KEY UPDATE id=id+1;
Query OK, 2 rows affected (0.00 sec)
mysql> select * from gg;
+----+------+
| id | name |
+----+------+
|? 1 | a??? |
|? 2 | b??? |
|? 4 | c??? |
+----+------+
3 rows in set (0.00 sec)
====================================================================
mysql> select * from gg;
+----+------+
| id | name |
+----+------+
|? 1 | a??? |
|? 2 | b??? |
|? 3 | c??? |
+----+------+
3 rows in set (0.00 sec)
mysql> replace into gg values(3,'d');
Query OK, 2 rows affected (0.00 sec)
mysql> select * from gg;?????????????
+----+------+
| id | name |
+----+------+
|? 1 | a??? |
|? 2 | b??? |
|? 3 | d??? |
+----+------+
3 rows in set (0.00 sec)
mysql>
本文转自 liang3391 51CTO博客，原文链接:http://blog.51cto.com/liang3391/853870
