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This article mainly introduces the sql sentence to modify the data method, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let the editor with you to understand.

Sql statement modifies data

In SQL, you can use UPDATE statements to modify and update the data of one or more tables.

The syntax format is:

UPDATE SET field 1 = value 1 [, field 2 = value 2... [WHERE clause] [ORDER BY clause] [LIMIT clause]

The syntax is as follows:

Used to specify the name of the table to update

SET clause: used to specify the column name to be modified in the table and its column value. Where each specified column value can be an expression or a default value for that column. If the default value is specified, the DEFAULT keyword is available to indicate the column value.

WHERE clause: optional. Used to limit the rows in the table to be modified. If not specified, all rows in the table are modified.

ORDER BY clause: optional. Used to limit the order in which rows in the table are modified.

LIMIT clause: optional. Used to limit the number of rows to be modified.

Note: when you modify multiple column values for a row of data, each value of the SET clause can be separated by a comma.

Example:

Mysql > UPDATE tb_courses_new-> SET course_name='DB',course_grade=3.5-> WHERE course_id=2;Query OK, 1 row affected (0.13 sec) Rows matched: 1 Changed: 1 Warnings: 0mysql > SELECT * FROM tb_courses_new +-+ | course_id | course_name | course_grade | course_info | +-+ -+ | 1 | Network | 4 | Computer Network | | 2 | DB | 3.5 | MySQL | 3 | Java | 4 | Java EE | | 4 | System | 4 | Operating System | +- -- + 4 rows in set (0.00 sec) Thank you for reading this article carefully I hope the article "the method of sql sentence to modify data" shared by the editor will be helpful to everyone. At the same time, I also hope that you will support and pay attention to the industry information channel. More related knowledge is waiting for you to learn!

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