What are the mysql update statements?

mysql update statements include: 1. UPDATE, used to update data in the table; 2. INSERT INTO... ON DUPLICATE KEY UPDATE, when inserting new records, if a key conflict is encountered, the update operation is performed; 3. , REPLACE INTO, perform update or insert operations based on primary key or unique index conflicts; 4. ALTER TABLE... ADD COLUMN, used to add new columns to existing tables, etc.

Operating system for this tutorial: Windows 10 system, MySQL version 8, Dell G3 computer.

Commonly used update statements in MySQL database include the following:

1. UPDATE: used to update data in the table. The common syntax is as follows:

复   UPDATE 表名 SET 列名1 = 值1, 列名2 = 值2 WHERE 条件;

2. INSERT INTO … ON DUPLICATE KEY UPDATE: When inserting a new record, if a key conflict is encountered, an update operation is performed. The common syntax is as follows:

   INSERT INTO 表名 (列1, 列2) VALUES (值1, 值2) ON DUPLICATE KEY UPDATE 列1 = 值1, 列2 = 值2;

3. REPLACE INTO: Perform an update or insert operation based on primary key or unique index conflict. The common syntax is as follows:

   REPLACE INTO 表名 (列1, 列2) VALUES (值1, 值2);

4. ALTER TABLE … ADD COLUMN: used to add new columns to an existing table. The common syntax is as follows:

   ALTER TABLE 表名 ADD COLUMN 列名 数据类型;

5. ALTER TABLE … MODIFY COLUMN: used to modify the definition of existing columns in the table. The common syntax is as follows:

   ALTER TABLE 表名 MODIFY COLUMN 列名 数据类型;

6. ALTER TABLE … DROP COLUMN: used to delete columns in the table. The common syntax is as follows:

   ALTER TABLE 表名 DROP COLUMN 列名;

These are commonly used update statements in MySQL. You can choose the appropriate statement to perform data update operations according to actual needs. Note that before performing any update operations, make sure you have the appropriate permissions and identify the tables and conditions you want to update.

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