How to use MySQL update command

1. Update syntax

The syntax format of the update command is as follows:

UPDATE table_name SET column1=value1,column2=value2,... WHERE some_column=some_value;

The points that need explanation are as follows:

• table_name: Specify the name of the table that needs to be modified.

• column1=value1,column2=value2,...: Multiple assignment statements are separated by "," to indicate the columns that need to be modified and the modified values.

• The conditional statement "WHERE some_column=some_value" is used to filter records that need to be modified. Only records that meet this condition will be modified. The column name that needs to be filtered is some_column, and the value that needs to be filtered is some_value.

Omitting conditional statements in the update command will cause all records in the table to be modified. You need to be very careful when using the update command and handle it with care.

2. Update Example

The following uses an example to demonstrate the actual use of the update command. Suppose there is a table named student, which includes several fields such as id, name, age, gender, class, etc. The information of student No. 001 needs to be modified to change his age to 20.

First, you need to log in to the MySQL database,

mysql -u root -p密码

Then, select the database that needs to be modified, for example, select the database named test:

use test;

Before executing the update command, please Make sure you give enough thought to what you're going to do. In this example, the execution instruction is as follows:

UPDATE student SET age = 20 WHERE id = '001';

The above instruction means to modify the age of the student with middle school number 001 in the student table to 20 years old. If the modification is successful, you will receive the following prompt:

Query OK, 1 row affected (0.01 sec)
Rows matched: 1 changed: 1 warnings: 0

Among them, "Query OK" means that the command was successfully executed, and 1 row affected means that the command affected 1 row, that is, the student information numbered 001 was successfully modified.

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