linux mysql delete

In the process of using Linux servers for web development and database management, MySQL database is the most commonly used one. However, in actual operation, sometimes it is necessary to delete the MySQL database or the data in the database, and the deletion operation is also a common operation. In this article, we will introduce in detail how to delete the MySQL database.

1. Delete MySQL database

First of all, it needs to be clear that deleting a MySQL database and deleting data in the MySQL database are two different operations. Before deleting the database, we need to make a backup first.

1.1 Back up data

Under Linux system, the mysqldump command is usually used to back up the MySQL database. This command can back up the entire data of the database or the specified data table to a .sql file. The following is a basic syntax:

$ mysqldump [options] db_name > db_name.sql

where db_name is the name of the database to be backed up. This command will back up the database to the db_name.sql file in the current directory.

1.2 Delete database

To delete the MySQL database, you need to log in to the MySQL server first. You can log in by using the following command:

$ mysql -u 用户名 -p

where the username is the username in the MySQL server, and you will be prompted to enter the password.

After logging in to the MySQL server, you can delete the database through the following command:

mysql> DROP DATABASE 数据库名;

The database name is the name of the database to be deleted.

2. Deleting data in the MySQL database

Different from deleting the MySQL database, deleting data in the database usually uses the DELETE statement.

2.1 Back up data

Similarly, you need to back up the data before deleting it. To back up data, use the mysqldump command mentioned earlier.

2.2 Delete data

The syntax for deleting data is as follows:

mysql> DELETE FROM 表名 [WHERE 条件];

Among them, the table name is the name of the data table to be operated, and the WHERE clause is optional. You can specify deletion The data meets the conditions.

If you want to delete the data in the entire table, you can use the following command:

mysql> DELETE FROM 表名;

If you want to delete the data that meets specific conditions, you can use the following command:

mysql> DELETE FROM 表名 WHERE 条件;

Among them, The conditions need to conform to the query condition syntax of MySQL.

3. Clear the data in the MySQL database

Sometimes you don’t need to delete the entire MySQL database or delete specific data, you just need to clear all the data in the data table. . At this time, you can use the TRUNCATE statement.

3.1 Back up data

Similarly, data backup is required before operation.

3.2 Clear the data table

The syntax for clearing the data table is as follows:

mysql> TRUNCATE TABLE 表名;

The table name is the name of the data table to be cleared.

Through the above three operations, you can delete, delete data or clear the data table of the MySQL database. To ensure normal operation, it is recommended to back up your data before proceeding. Also note that these operations are irreversible, so proceed with caution.

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