How to insert and update data in MySQL?

How to insert and update data in MySQL?

MySQL is an open source relational database management system that is widely used for data storage and management of web applications. In MySQL, inserting and updating data are very common operations. This article will introduce how to use MySQL to insert and update data, and provide some code examples.

1. Data insertion operation

To insert data into MySQL, you can use the INSERT INTO statement. The INSERT INTO statement inserts a record into a database table. The following is an example of inserting data:

INSERT INTO table_name (column1, column2, column3,...)
VALUES (value1, value2, value3,...);

In this example, table_name is the name of the table where data is to be inserted, column1, column2, etc. are the column names in the table, and value1, value2, etc. are the values ​​to be inserted.

For example, we have a table named "students" with three columns: "id", "name" and "age". If you want to insert a record into this table, you can use the following code:

INSERT INTO students (id, name, age)
VALUES (1, 'Zhang San', 20);

This statement will insert a record with ID 1, name "Zhang San" and age 20 in the "students" table.

If you want to insert multiple records, you can use the following code:

INSERT INTO students (id, name, age)
VALUES (2, '李思', 22),

   (3, '王五', 21),
   (4, '赵六', 23);

This statement will insert three records into the "students" table, namely the record with id 2, name "Li Si", age 22; id 3, name "Wang Wu", The record with age 21; and the record with id 4, name "Zhao Liu" and age 23.

2. Data update operation

In MySQL, you can use the UPDATE statement to update data. The UPDATE statement can update records in the table based on conditions. The following is an example of updating data:

UPDATE table_name
SET column1 = value1, column2 = value2,...
WHERE condition;

In this example, table_name is The table name of the data to be updated, column1, column2, etc. are the column names to be updated, value1, value2, etc. are the values ​​​​to be updated, and condition is the condition used to filter the records to be updated.

For example, if we want to update the age of the record with id 1 in the "students" table to 25, we can use the following code:

UPDATE students
SET age = 25
WHERE id = 1;

This statement will update the age of the record with id 1 in the "students" table to 25.

If you want to update multiple fields, you can use the following code:

UPDATE students
SET age = 23, name = 'Zhao Qi'
WHERE id = 4;

This statement will update the age of the record with id 4 in the "students" table to 23, and update the name to "Zhao Qi".

3. Summary

This article introduces how to insert and update data in MySQL. New records can be inserted into the table by using the INSERT INTO statement, and records in the table can be updated based on conditions using the UPDATE statement. In practical applications, we can flexibly use these operations to manage and maintain data as needed.

Code example:

Example of inserting data:

INSERT INTO students (id, name, age)
VALUES (1, 'Zhang San', 20) ;

INSERT INTO students (id, name, age)
VALUES (2, '李思', 22),

   (3, '王五', 21),
   (4, '赵六', 23);

Example of updating data:

UPDATE students
SET age = 25
WHERE id = 1;

UPDATE students
SET age = 23, name = 'Zhao Qi'
WHERE id = 4;

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