Detailed explanation of MySQL operations: teach you step by step how to insert, modify, and delete data

MySQL is a popular relational database management system that can be used to store and manage various types of data. Using MySQL, you can easily insert, modify, and delete data. This article will explain how to perform these operations through MySQL.

1. Connecting to MySQL

Before you begin, you need to connect to the MySQL database. You can use the MySQL command line client or any other MySQL client. In this example we will use the command line client.

To connect to MySQL, open a terminal or command prompt and type the following command:

mysql -u用户名 -p密码

where username is your MySQL username and password is your MySQL password. After pressing the Enter key, you will be prompted for your password. After entering the password, press Enter to connect to MySQL.

2. Create database

Before inserting, modifying, and deleting data, you need to create a database in MySQL. To create a database, use the following command:

CREATE DATABASE 数据库名;

where databasename is the name of the database you wish to create. After pressing the Enter key, MySQL will create a new database.

3. Select Database

Before doing anything with MySQL, you need to select the database you want to use. To select a database, use the following command:

USE 数据库名;

where databasename is the name of the database you want to use. After pressing the Enter key, MySQL will select the database and you can perform any operation in the database.

4. Insert data

To insert data into a MySQL database, you need to use the INSERT INTO statement. Here is an example of inserting data:

INSERT INTO 表名 (字段1, 字段2, 字段3) VALUES (值1, 值2, 值3);

where tablename is the name of the table into which you want to insert data, and field is the field name in the table, from the column after the opening bracket. value is the value to be inserted into the field, from the column after the closing bracket.

For example, to insert a new customer named "John Smith" into the customer table, you can use the following command:

INSERT INTO customer (first_name, last_name) VALUES ('John', 'Smith');

After running this command, MySQL will add a new row to the customer table, The first_name field is "John" and the last_name field is "Smith".

5. Modify data

To modify the data in the MySQL database, you need to use the UPDATE statement. The following is an example of modifying data:

UPDATE 表名 SET 字段 = 值 WHERE 条件;

Where table name is the name of the table you want to modify data, field is the name of the field you want to modify, and value is the new value you want to set the field to. Condition is an optional option that specifies the conditions for the rows to be modified.

For example, to change the last name of a customer named "John Smith" in the customer table to "Johnson", you can use the following command:

UPDATE customer SET last_name='Johnson' WHERE first_name='John' AND last_name='Smith';

After running this command, MySQL will change customer All customers named "John Smith" in the table have a last_name field of "Johnson".

6. Delete Data

To delete data from a MySQL database, you need to use the DELETE FROM statement. Here is an example of deleting data:

DELETE FROM 表名 WHERE 条件;

where tablename is the name of the table from which you want to delete data. Condition is optional and allows you to specify conditions for rows to be deleted.

For example, to delete all customers named "John Smith" from the customer table, use the following command:

DELETE FROM customer WHERE first_name='John' AND last_name='Smith';

After running this command, MySQL will delete all customers named "John Smith" from the customer table For a client of "John Smith".

7. Conclusion

Using MySQL, you can easily insert, modify and delete data. You can perform various operations in MySQL by connecting to MySQL, creating a database, selecting a database, inserting data, modifying data, and deleting data. In addition to these basic operations, MySQL also provides many other functions and commands that can help you manage and manipulate data easily.

The above is the detailed content of Detailed explanation of MySQL operations: teach you step by step how to insert, modify, and delete data. For more information, please follow other related articles on the PHP Chinese website!