mysql insert replace

`INSERT REPLACE` 是 MySQL 中的一种语句，其作用是先尝试插入一行数据，如果该行数据已经存在（根据唯一索引或主键判断），则将已存在的行删除，再插入新的数据。

例如，如果有一个表 `users`，其中有一个唯一索引 `username`，现在想要插入一条记录，如果该记录已经存在，则先删除已经存在的记录，再插入新的记录。可以使用以下语句：

INSERT INTO users (username, password) VALUES ('john', '123456')
  ON DUPLICATE KEY UPDATE password='123456';

注意，这里使用的是 `INSERT INTO ... ON DUPLICATE KEY UPDATE` 语法，而不是 `INSERT REPLACE`。因为 `INSERT REPLACE` 语句在执行时，会先删除已经存在的记录，再插入新的记录。但是使用 `INSERT INTO ... ON DUPLICATE KEY UPDATE` 语法可以避免这一点，因为它只会更新已经存在的记录，而不会删除记录。

相关问题

mysql insert or replace 使用

MySQL does not have an `INSERT OR REPLACE` statement like SQLite. However, you can achieve similar functionality using the `INSERT INTO ... ON DUPLICATE KEY UPDATE` statement.

Assuming you have a table named `my_table` with columns `id`, `name`, and `age`, and `id` is the primary key column, you can use the following syntax to insert a new row or update an existing row with the same `id` value:

INSERT INTO my_table (id, name, age) VALUES (1, 'John', 30)
  ON DUPLICATE KEY UPDATE name = VALUES(name), age = VALUES(age);

In this example, if a row with `id` = 1 already exists, it will update the `name` and `age` columns with the new values. If no row with `id` = 1 exists, it will insert a new row with the specified values.

Note that `VALUES(name)` and `VALUES(age)` refer to the values specified in the `INSERT` statement. This allows you to update the row with the new values if it already exists.

MySQL insert 换成 replace

可以使用"replace into"语句来替代"insert into"语句。"replace into"语句的语法是：replace into tableX (column1, column2) values (value1, value2)。这样可以实现在插入数据时，如果数据已经存在，则会先删除原有数据，再插入新的数据。这样可以避免重复插入数据的问题。\[2\]
#### 引用[.reference_title]
- *1* *2* [Mysql replace/insert into 插入修改数据](https://blog.csdn.net/qq_35461948/article/details/113625161)[target="_blank" data-report-click={"spm":"1018.2226.3001.9630","extra":{"utm_source":"vip_chatgpt_common_search_pc_result","utm_medium":"distribute.pc_search_result.none-task-cask-2~all~insert_cask~default-1-null.142^v91^insert_down1,239^v3^insert_chatgpt"}} ] [.reference_item]
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