发布时间:2025-11-05 10:40:13 来源:创站工坊 作者:人工智能

replace into和insert into on 避免duplicate key 区别
replace的用法
当不冲突时相当于insert,其余列默认值 当key冲突时,换逻自增列更新,坑爹操replace冲突列,避免其余列默认值 Com_replace会加1 Innodb_rows_updated会加1Insert into …on duplicate key的换逻用法
不冲突时相当于insert,其余列默认值 当与key冲突时,坑爹操只update相应字段值。避免 Com_insert会加1 Innodb_rows_inserted会增加1实验展示
表结构
create table helei1( id int(10) unsigned NOT NULL AUTO_INCREMENT,换逻 name varchar(20) NOT NULL DEFAULT , age tinyint(3) unsigned NOT NULL default 0, PRIMARY KEY(id), UNIQUE KEY uk_name (name) ) ENGINE=innodb AUTO_INCREMENT=1 DEFAULT CHARSET=utf8; </br>表数据
root@127.0.0.1 (helei)> select * from helei1; +----+-----------+-----+ | id | name | age | +----+-----------+-----+ | 1 | 贺磊 | 26 | | 2 | 小明 | 28 | | 3 | 小红 | 26 | +----+-----------+-----+ 3 rows in set (0.00 sec)replace into用法
root@127.0.0.1 (helei)> replace into helei1 (name) values(贺磊); Query OK, 2 rows affected (0.00 sec) root@127.0.0.1 (helei)> select * from helei1; +----+-----------+-----+ | id | name | age | +----+-----------+-----+ | 2 | 小明 | 28 | | 3 | 小红 | 26 | | 4 | 贺磊 | 0 | +----+-----------+-----+ 3 rows in set (0.00 sec) root@127.0.0.1 (helei)> replace into helei1 (name) values(爱璇); Query OK, 1 row affected (0.00 sec) root@127.0.0.1 (helei)> select * from helei1; +----+-----------+-----+ | id | name | age | +----+-----------+-----+ | 2 | 小明 | 28 | | 3 | 小红 | 26 | | 4 | 贺磊 | 0 | | 5 | 爱璇 | 0 | +----+-----------+-----+ 4 rows in set (0.00 sec)replace的用法
当没有key冲突时,企商汇replace into 相当于insert,坑爹操其余列默认值
当key冲突时,避免自增列更新,换逻replace冲突列,坑爹操其余列默认值
Insert into …on duplicate key:
root@127.0.0.1 (helei)> select * from helei1; +----+-----------+-----+ | id | name | age | +----+-----------+-----+ | 2 | 小明 | 28 | | 3 | 小红 | 26 | | 4 | 贺磊 | 0 | | 5 | 爱璇 | 0 | +----+-----------+-----+ 4 rows in set (0.00 sec) root@127.0.0.1 (helei)> insert into helei1 (name,避免age) values(贺磊,0) on duplicate key update age=100; Query OK, 2 rows affected (0.00 sec) root@127.0.0.1 (helei)> select * from helei1; +----+-----------+-----+ | id | name | age | +----+-----------+-----+ | 2 | 小明 | 28 | | 3 | 小红 | 26 | | 4 | 贺磊 | 100 | | 5 | 爱璇 | 0 | +----+-----------+-----+ 4 rows in set (0.00 sec) root@127.0.0.1 (helei)> select * from helei1; +----+-----------+-----+ | id | name | age | +----+-----------+-----+ | 2 | 小明 | 28 | | 3 | 小红 | 26 | | 4 | 贺磊 | 100 | | 5 | 爱璇 | 0 | +----+-----------+-----+ 4 rows in set (0.00 sec) root@127.0.0.1 (helei)> insert into helei1 (name) values(爱璇) on duplicate key update age=120; Query OK, 2 rows affected (0.01 sec) root@127.0.0.1 (helei)> select * from helei1; +----+-----------+-----+ | id | name | age | +----+-----------+-----+ | 2 | 小明 | 28 | | 3 | 小红 | 26 | | 4 | 贺磊 | 100 | | 5 | 爱璇 | 120 | +----+-----------+-----+ 4 rows in set (0.00 sec) root@127.0.0.1 (helei)> insert into helei1 (name) values(不存在) on duplicate key update age=80; Query OK, 1 row affected (0.00 sec) root@127.0.0.1 (helei)> select * from helei1; +----+-----------+-----+ | id | name | age | +----+-----------+-----+ | 2 | 小明 | 28 | | 3 | 小红 | 26 | | 4 | 贺磊 | 100 | | 5 | 爱璇 | 120 | | 8 | 不存在 | 0 | +----+-----------+-----+ 5 rows in set (0.00 sec)总结
replace into这种用法,相当于如果发现冲突键,换逻先做一个delete操作,坑爹操再做一个insert 操作,未指定的列使用默认值,香港云服务器这种情况会导致自增主键产生变化,如果表中存在外键或者业务逻辑上依赖主键,那么会出现异常。因此建议使用Insert into …on duplicate key。由于编写时间也很仓促,文中难免会出现一些错误或者不准确的地方,不妥之处恳请读者批评指正。
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