mysql delete data in table

MySQL is an open source relational database management system and a very popular database. When using MySQL, it is often necessary to delete data in the table. In this article, we will explore how to delete data from a table using MySQL.

1. Use the DELETE statement to delete data from the table

MySQL provides the DELETE statement to delete data from the table. The DELETE statement can delete single or multiple data rows. If you use the DELETE statement without specifying a WHERE clause, all data in the table will be deleted.

Syntax:

DELETE FROM table name WHERE condition;

• Table name: The name of the table where data needs to be deleted.
• Conditions: Optional, specify the data rows that need to be deleted.

For example, we have a table named students with the following data:

##1Alice25Female##2##3Charlie23Male We can delete the data of students younger than 25 years old using the following command:

DELETE FROM students WHERE age < 25;

id	name	age	gender
Bob	26	Male

After executing the above command, the data in the students table will become:

##idname2BobUse the TRUNCATE TABLE statement to delete data in the table

age	gender
26	Male

In addition to using the DELETE statement, MySQL also provides the TRUNCATE TABLE statement to delete the table data. The TRUNCATE TABLE statement deletes all data in the table and releases the storage space occupied by the table. It also resets the table counters and all indexes and constraints related to the table.
2. Syntax:

TRUNCATE TABLE table name;

Table name: The name of the table where data needs to be deleted.

For example, we can use the following command to delete all data in the students table:

• TRUNCATE TABLE students;

After executing the above command, there will no longer be any data in the students table.

Notes

When using the DELETE statement to delete data, you need to pay attention to the following points:

When no WHERE clause is specified, DELETE statement will delete all data in the table.

When you use the DELETE statement to delete data, the deleted data will not be recoverable. Therefore, before executing the DELETE statement, please carefully consider whether the data needs to be deleted.

• If you need to delete a large amount of data, please consider using the TRUNCATE TABLE statement to improve deletion efficiency.
• Conclusion

In MySQL, we can use DELETE and TRUNCATE TABLE statements to delete data in a table. The DELETE statement can be used to delete single or multiple data rows, while the TRUNCATE TABLE statement can delete all data in the table and release the storage space occupied by the table. When deleting data, please pay attention to the importance of the data and the deletion efficiency to make the best decision.

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