INSERT INTO 、INSERT IGNORE INTO 、REPLACE INTO 、ON DUPLICATE KEY ON 关系

1. 首先我们先创建一张简单的用户表；

   CREATE TABLE `person` (
     `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
     `name` varchar(20) NOT NULL,
     `age` tinyint(2) NOT NULL DEFAULT '0',
     PRIMARY KEY (`id`),
     UNIQUE KEY `name` (`name`)
   ) ENGINE=InnoDB;

    

2. INSERT INTO

   MySQL [company]> INSERT INTO `person` (name, age) VALUES ('Lewis', 20);   # 新增记录
   Query OK, 1 row affected (0.01 sec)
   
   MySQL [company]> SELECT * FROM person;   # 查询信息
   +----+-------+-----+
   | id | name  | age |
   +----+-------+-----+
   |  1 | Lewis |  20 |
   +----+-------+-----+
   1 row in set (0.00 sec)
   

    

3. INSERT IGNORE INTO 表示新增数据PRIMARY KEY索引或则UNIQUE索引存在重复值，则提示warning，或略此次新增；否则就相当于INSERT INTO；

   MySQL [company]> INSERT IGNORE INTO `person` (name, age) VALUES ('Lewis', 22);
   Query OK, 0 rows affected, 1 warning (0.01 sec)   # name相同，提示warning ,0条记录被影响
   
   MySQL [company]> SELECT * FROM person;
   +----+-------+-----+
   | id | name  | age |
   +----+-------+-----+
   |  1 | Lewis |  20 |
   +----+-------+-----+
   1 row in set (0.00 sec)
   
   MySQL [company]> INSERT IGNORE INTO `person` (id, name, age) VALUES (1 ,'Helen', 20);
   Query OK, 0 rows affected, 1 warning (0.00 sec)   # id相同，提示warning ,0条记录被影响
   
   MySQL [company]> SELECT * FROM person;
   +----+-------+-----+
   | id | name  | age |
   +----+-------+-----+
   |  1 | Lewis |  20 |
   +----+-------+-----+
   1 row in set (0.01 sec)
   
   MySQL [company]> INSERT IGNORE INTO `person` (name, age) VALUES ('Helen', 20);
   Query OK, 1 row affected (0.01 sec)   # 没有primary key 或则 unique 值相同，新增1条记录
   
   MySQL [company]> SELECT * FROM person;
   +----+-------+-----+
   | id | name  | age |
   +----+-------+-----+
   |  1 | Lewis |  20 |
   |  3 | Helen |  20 |
   +----+-------+-----+
   2 rows in set (0.00 sec)
   
   

    

4. REPLACE INTO 表示新增数据PRIMARY KEY索引或则UNIQUE索引存在重复值，则替换其字段数据，否则效果同INSERT INTO；

   MySQL [company]> REPLACE INTO person (name, age) VALUES ('Lewis', 30);
   Query OK, 2 rows affected (0.00 sec)
   
   MySQL [company]> SELECT * FROM person;
   +----+-------+-----+
   | id | name  | age |
   +----+-------+-----+
   |  3 | Helen |  20 |
   |  4 | Lewis |  30 |
   +----+-------+-----+
   2 rows in set (0.00 sec)
   
   MySQL [company]> REPLACE INTO person (name, age) VALUES ('Alice', 18);
   Query OK, 1 row affected (0.00 sec)
   
   MySQL [company]> SELECT * FROM person;
   +----+-------+-----+
   | id | name  | age |
   +----+-------+-----+
   |  3 | Helen |  20 |
   |  4 | Lewis |  30 |
   |  5 | Alice |  18 |
   +----+-------+-----+
   3 rows in set (0.00 sec)
   

    

5. ON DUPLICATE KEY UPDATE 表示新增数据PRIMARY KEY索引或则UNIQUE索引存在重复值，则执行更新操作，否则效果同INSERT INTO；

   MySQL [company]> INSERT INTO person (name, age) VALUES ('Helen', 15) ON DUPLICATE KEY UPDATE age = age - 5;
   Query OK, 2 rows affected (0.01 sec)
   
   MySQL [company]> SELECT * FROM person;
   +----+-------+-----+
   | id | name  | age |
   +----+-------+-----+
   |  3 | Helen |  15 |
   |  4 | Lewis |  30 |
   |  5 | Alice |  18 |
   +----+-------+-----+
   3 rows in set (0.00 sec)
   
   MySQL [company]> INSERT INTO person (name, age) VALUES ('Gere', 10) ON DUPLICATE KEY UPDATE age = age - 5;
   Query OK, 1 row affected (0.00 sec)
   
   MySQL [company]> SELECT * FROM person;
   +----+-------+-----+
   | id | name  | age |
   +----+-------+-----+
   |  3 | Helen |  15 |
   |  4 | Lewis |  30 |
   |  5 | Alice |  18 |
   |  7 | Gere  |  10 |
   +----+-------+-----+
   4 rows in set (0.00 sec)