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MySQL database basic command collection Collection of essential operation instructions for beginners
MySQL database basic command collection Collection of essential operation instructions for beginners
May 22, 2025 pm 11:45 PM
Newcomers need to master the basic MySQL commands, because these commands are the basic tools for operating databases, helping to understand the principles of the database and improve work efficiency. Specifically include: 1. Connect to MySQL server: mysql -u username -p; 2. Create database and tables: CREATE DATABASE my_database; USE my_database; CREATE TABLE users (id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(100) NOT NULL, email VARCHAR(100) NOT NULL UNIQUE); 3. Insert data: INSERT INTO users (name, email) VALUES ('John Doe', 'john@example.com'); 4. Query data: SELECT FROM users; SELECT name, email FROM users; SELECT FROM users WHERE name = 'John Doe'; 5. Update data: UPDATE users SET email = 'newemail@example.com' WHERE name = 'John Doe'; 6. Delete data: DELETE FROM users WHERE name = 'John Doe'; 7. Performance optimization: Avoid using SELECT * and use indexes such as CREATE INDEX idx_email ON users(email); 8. Best practices: Good naming habits, regular backups, and use transactions to ensure data consistency.
Before starting our topic today - the MySQL database basic command collection, let me answer a common question: Why do newbies need to master these basic commands?
MySQL is one of the most popular open source databases in the world and is widely used in projects of all sizes. As a novice, mastering these basic commands is not only a need to operate the database, but also a preliminary cultivation of database management and design thinking. Through these commands, you can not only perform basic data operations, but also understand how the database works, which is crucial for future advanced operations and optimizations. More importantly, these commands are the basic tools for you to interact with the database. Proficient in them can greatly improve your productivity and avoid common mistakes.
Now, let's dive into these essential MySQL operation instructions.
When you first come into contact with MySQL, you may feel a little overwhelmed. The concept of database, table design, and data addition, deletion, modification and search are all thresholds that novices need to cross. Don't worry, here I will share some of my own experiences and experiences when learning MySQL, hoping that they can help you get started quickly.
First, we need to know how to connect to the MySQL server. Use the following command:
mysql -u username -p
After entering the password, you enter the command line interface of MySQL. Here, -u represents the user name and -p represents the password. Remember to replace username and password with your own username and password .
Next, we need to learn how to create databases and tables. Suppose we want to create a database called my_database , we can use the following command:
CREATE DATABASE my_database;
Then, we enter this database:
USE my_database;
Now, let's create a table. Suppose we want to create a table named users , including three fields: id , name and email :
CREATE TABLE users (
id INT AUTO_INCREMENT PRIMARY KEY,
name VARCHAR(100) NOT NULL,
email VARCHAR(100) NOT NULL UNIQUE
); Here AUTO_INCREMENT means that id will be incremented automatically, PRIMARY KEY means that this is the primary key, NOT NULL means that the field cannot be empty, UNIQUE means that the value of the field must be unique.
After creating the table, we need to know how to insert data into the table. Suppose we want to insert a record:
INSERT INTO users (name, email) VALUES ('John Doe', 'john@example.com');
Next, we need to know how to query the data. The most basic query is:
SELECT * FROM users;
This returns all records in the users table. If you want to view only specific fields, you can do this:
SELECT name, email FROM users;
If you want to query based on certain conditions, you can use the WHERE clause. For example, find a user with the name John Doe:
SELECT * FROM users WHERE name = 'John Doe';
Update data is also a common operation. Suppose we want to update John Doe's email address:
UPDATE users SET email = 'newemail@example.com' WHERE name = 'John Doe';
Deletion of data is also essential. Suppose we want to delete John Doe's record:
DELETE FROM users WHERE name = 'John Doe';
In practice, you may encounter some common problems. For example, forgetting to put quotes causes a syntax error, or forgetting to use the WHERE clause causes all records to be deleted. These are common mistakes for beginners, so be careful.
There are several points to pay attention to when it comes to performance optimization. First, try to avoid using SELECT * , and select only the fields you need. Secondly, using indexes can greatly improve query speed. For example, we can create an index on the email field:
CREATE INDEX idx_email ON users(email);
In this way, when we query based on our email address, the speed will be greatly improved.
Finally, share some best practices I have summarized in my actual project. First, develop good naming habits and use meaningful table names and field names. Secondly, back up the database regularly to prevent data loss. Finally, learning to use transactions can ensure the consistency and integrity of the data.
START TRANSACTION; INSERT INTO users (name, email) VALUES ('Jane Doe', 'jane@example.com'); UPDATE users SET email = 'newemail@example.com' WHERE name = 'John Doe'; COMMIT;
With these commands and tricks, you should be able to better operate the MySQL database. I hope these sharing can help you get started quickly and be at ease in actual projects. If you have any questions or need further guidance, please feel free to communicate.
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