How to delete mysql data

MySQL is a very popular relational database management system. However, when using MySQL, you will inevitably encounter situations where data needs to be deleted. How to delete data quickly and efficiently? Next, this article will explain the following aspects.

1. Delete a single piece of data

In MySQL, deleting a single piece of data is the most basic operation. The syntax is as follows:

DELETE FROM table_name WHERE condition;

Among them, table_name is the table name, and condition is the condition for deleting data. What needs to be noted here is that if the WHERE condition is not added, the data in the entire table will be deleted. Therefore, the conditions must be accurate when deleting.

2. Delete multiple pieces of data

If you need to delete multiple pieces of data, you can use IN or BETWEEN to limit the conditions . The syntax is as follows:

DELETE FROM table_name WHERE column_name IN (value1, value2, ...);

or

DELETE FROM table_name WHERE column_name BETWEEN value1 AND value2;

Among them, column_name is the name of the column to be deleted, value1, value2, ... means to delete specific value.

3. Delete the data of the entire table

To delete the data of the entire table, you can use the TRUNCATE keyword. The syntax is as follows:

TRUNCATE TABLE table_name;

This statement will delete all data in the entire table, but will retain the structure of the table, so it needs to be used with caution.

4. Delete the specified number of rows

Sometimes you need to delete the specified number of rows of data, you can use the LIMIT keyword. The syntax is as follows:

DELETE FROM table_name WHERE condition LIMIT num;

Among them, num represents the number of rows to be deleted.

5. Delete table

If you want to delete the entire table, you can use the DROP statement. The syntax is as follows:

DROP TABLE table_name;

This statement will completely delete the entire table, including table structure and data, so it needs to be used with caution.

The above are the common methods for deleting data in MySQL. It should be noted that deleting data is a very dangerous operation and must be done on a case-by-case basis, and the data must be backed up just in case. After the deletion operation is completed, you need to promptly check whether the data has been deleted and no junk data is left behind.

In short, through the introduction of this article, I believe that everyone has an in-depth understanding of the method of deleting data in MySQL, and I hope it can be helpful to everyone in actual use.

The above is the detailed content of How to delete mysql data. For more information, please follow other related articles on the PHP Chinese website!