How to delete delete in mysql

In database management, deletion operation is a very important operation. As the most popular relational database management software in the world, MySQL helps users complete various operations through its powerful functions, among which database deletion operation is also one of its important functions. This article will focus on the MySQL deletion operation so that readers can master the basic knowledge about the MySQL deletion operation.

1. Introduction to deletion operation

MySQL deletion operation mainly refers to deleting data table entries in the database. Before performing the deletion operation, you need to query and locate the table items to be deleted to avoid affecting other tables. Under normal circumstances, we can complete the deletion operation through SQL statements. There are two ways to delete SQL statements: single row deletion and batch deletion.

2. Single row deletion operation

The single row deletion operation is mainly to delete a single data table record. The SQL statement format is:

DELETE FROM 表名称 WHERE 条件;

Among them, the keyword DELETE means deletion For data operations, FROM indicates which table to delete from, and WHERE indicates the specific conditions for deletion. There can be multiple conditions here, and multiple conditions are connected using AND or OR.

Let’s take the example of deleting the student whose middle school number is 2021001 in the student information table:

DELETE FROM studentinfo WHERE id=2021001;

3. Batch deletion operation

The batch deletion operation is mainly based on the number of students who meet the conditions. To delete records, the SQL statement format is:

DELETE FROM 表名称 WHERE 条件1 AND 条件2 AND ... AND 条件n;

Among them, the condition refers to the condition for deletion, and multiple conditions can be connected using AND or OR. Below we take the example of deleting all students who failed:

DELETE FROM studentinfo WHERE score<60;

IV. Key points of deletion operation

MySQL deletion operation will permanently delete the data from the database every time, so when executing When deleting, you need to pay attention to the following aspects.

1. Back up data

Before performing the deletion operation, we need to back up the data so that we can quickly restore the data if it is accidentally deleted.

2. Conditional filtering

When performing a deletion operation, it is necessary to filter according to specific conditions to avoid deleting wrong data.

3. Confirm before deletion

Before performing the deletion operation, you need to confirm the data to be deleted to ensure the accuracy of the data.

4. Transaction control

When performing a deletion operation, it is necessary to consider the combination with transaction control to ensure the consistency and integrity of the deletion operation.

In short, the MySQL deletion operation is one of the basic operations in data management, and it is also a very important operation and should be used flexibly according to the actual situation. This article mainly introduces the basic syntax and operation points of MySQL deletion operations in detail. I hope readers can master the basic knowledge of MySQL deletion operations.

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