mysql中insert ignore、insert和replace的区别及说明

CREATE TABLE names(
  id INT(10) PRIMARY KEY AUTO_INCREMENT,
  name VARCHAR(255) UNIQUE,
  age INT(10)
)

Mysql> insert into names(name, age) values("小明", 24);
mysql> insert into names(name, age) values("大红", 24);
mysql> insert into names(name, age) values("大壮", 24);
mysql> insert into names(name, age) values("秀英", 24);

mysql> select * from names;
+----+--------+------+
| id | name  | age |
+----+--------+------+
| 1 | 小明  |  24 |
| 2 | 大红  |  24 |
| 3 | 大壮  |  24 |
| 4 | 秀英  |  24 |
+----+--------+------+

mysql> insert into names(name, age) values("小明", 23);

ERROR 1062 (23000): Duplicate entry '小明' for key 'name'

mysql> replace into names(name, age) values("小明", 23);
Query OK, 2 rows affected (0.00 sec)

mysql> select * from names;
+----+--------+------+
| id | name  | age |
+----+--------+------+
| 2 | 大红  |  24 |
| 3 | 大壮  |  24 |
| 4 | 秀英  |  24 |
| 6 | 小明  |  23 |
+----+--------+------+

mysql> replace into names(name, age) values("大名", 23);
Query OK, 1 row affected (0.00 sec)

mysql> select * from names;
+----+--------+------+
| id | name  | age |
+----+--------+------+
| 2 | 大红  |  24 |
| 3 | 大壮  |  24 |
| 4 | 秀英  |  24 |
| 6 | 小明  |  23 |
| 7 | 大名  |  23 |
+----+--------+------+

mysql> insert ignore into names(name, age) values("大壮", 25);
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> insert ignore into names(name, age) values("壮壮", 25);
Query OK, 1 row affected (0.01 sec)

mysql> select * from names;
+----+--------+------+
| id | name  | age |
+----+--------+------+
| 2 | 大红  |  24 |
| 3 | 大壮  |  24 |
| 4 | 秀英  |  24 |
| 6 | 小明  |  23 |
| 7 | 大名  |  23 |
| 10 | 壮壮  |  25 |
+----+--------+------+