表要求：有PrimaryKey，或者unique索引
结果：表id都会自增
测试代码
创建表
CREATE TABLE names( id INT(10) PRIMARY KEY AUTO_INCREMENT, name VARCHAR(255) UNIQUE, age INT(10) )
插入数据
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 | +----+--------+------+
insert
插入已存在, id会自增，但是插入不成功，会报错
mysql> insert into names(name, age) values("小明", 23); ERROR 1062 (23000): Duplicate entry '小明' for key 'name'
replace
已存在替换，删除原来的记录，添加新的记录
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 | +----+--------+------+
不存在替换，添加新的记录
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 | +----+--------+------+
insert ignore
插入已存在，忽略新插入的记录，id会自增，不会报错
mysql> insert ignore into names(name, age) values("大壮", 25); Query OK, 0 rows affected, 1 warning (0.00 sec)
插入不存在，添加新的记录
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 | +----+--------+------+
