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:

DELETE FROM students WHERE age < 25;

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.
Syntax:

TRUNCATE TABLE table name;

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

• TRUNCATE TABLE students;

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  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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