mysql batch modification

In MySQL, batch modification requires the use of SQL statements.

SQL statements are a standard language for relational databases that can be used to manage and operate data in the database. Through SQL statements, we can batch modify, add or delete data in the database.

In MySQL, batch modification operations can be implemented using the UPDATE statement. The UPDATE statement can be used to modify one record or multiple records in a table. The specific syntax is as follows:

UPDATE 表名 SET 字段 = 新值 WHERE 条件;

Among them, the table name represents the name of the table to be modified; the field represents the column name to be modified; the new value represents the new value to be modified; the condition represents filtering the records to be modified. Commonly used filtering conditions include =, >, <, >=, <=, LIKE, etc.

The following uses examples to introduce in detail how to use the UPDATE statement to make batch modifications.

1. Modify the value of a single field

Suppose there is a table named student, containing the following fields:

id: student number
name : Student name
score: Student score
class: Student class

Now it is necessary to change the classes of all students with the surname Li to Class 1. This can be achieved using the following SQL statement:

UPDATE student SET class = '1' WHERE name LIKE '李%';

This statement will filter out all student records whose names begin with "李" and change their class to Class 1.

2. Modify the values ​​of multiple fields

If you need to modify the values ​​of multiple fields, just fill in the column names that need to be modified and the corresponding new values ​​in sequence after SET. Can. For example, the class and grade of a student whose surname is Zhang and whose score is less than 60 need to be modified to class 2 and 60 points. This can be achieved using the following SQL statement:

UPDATE student SET class = '2', score = '60' WHERE name LIKE '张%' AND score < 60;

This statement will filter out all student records whose names start with "Zhang" and whose grades are less than 60 points, and change their class to Class 2 and their grades to 60 point.

3. Batch modify the values ​​of all records

If you need to modify the value of a column of all records in the table, you can use the following SQL statement to achieve it:

UPDATE student SET score = score + 10;

This statement will modify the score column of the student table so that each student's score will be increased by 10 points.

Summary

It is a common requirement to perform batch modification operations in MySQL. Through the UPDATE statement, you can easily modify the values ​​of multiple records in the table and improve data management efficiency. In actual use, you need to carefully understand the syntax and usage of SQL statements to avoid problems such as misoperation and data loss.

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