What are the skills that MySQL must master? - Getting Started Guide
Introduction: MySQL is a commonly used relational database management system that is widely used in the development of Web applications. Whether you are advancing your career or supporting your company's business, mastering MySQL skills is crucial. This article will introduce some basic concepts and common operations of MySQL to help readers get started and establish a solid database foundation.
1. Introduction and installation
MySQL is an open source database management system developed by the Swedish MySQL AB company and later acquired by Oracle. It supports multiple operating systems, including Windows, Linux, MacOS, etc. To learn MySQL, you first need to install the MySQL software.
mysql -u root -p.2. Basic operations
Create database
In MySQL, we can use theCREATE DATABASEstatement to create a database. For example, to create a database named "mydatabase", you can execute the following command:
CREATE DATABASE mydatabase;
Create table
Create table is the basic unit of storing data in the database. We can use theCREATE TABLEstatement to create a table. The following is an example of creating a table named "students":
CREATE TABLE students ( id INT PRIMARY KEY, name VARCHAR(100), age INT, gender VARCHAR(10) );
Insert data
Use theINSERT INTOstatement to insert data into the table. The following is an example of inserting a record into the "students" table:
INSERT INTO students (id, name, age, gender) VALUES (1, 'Tom', 20, 'Male');
Querying data
Use theSELECTstatement to retrieve data from the table. The following is an example of querying all records in the "students" table:
SELECT * FROM students;
Update data
Use theUPDATEstatement to update the data in the table. The following is an example of changing the name of the record with id 1 in the "students" table to "John":
UPDATE students SET name='John' WHERE id=1;
Delete data
UseDELETE FROMstatement can delete data from the table. The following is an example of deleting records with gender "Female" in the "students" table:
DELETE FROM students WHERE gender='Female';
3. Advanced operations
Using indexes
Index is an important means to improve database query efficiency. We can create an index in a table using theCREATE INDEXstatement. The following is an example of creating an index on the "age" column in the "students" table:
CREATE INDEX idx_age ON students (age);
Union query
Union query is retrieved by joining two or more tables An operation on data. The following is an example of querying related data in the "students" table and "courses" table:
SELECT students.name, courses.course_name FROM students JOIN courses ON students.id = courses.student_id;
Using transactions
A transaction is a set of SQL operations that either all execute successfully or All failed and rolled back. Using transactions ensures the consistency and reliability of data in the database. The following is an example of using transactions:
START TRANSACTION; UPDATE account SET balance = balance - 100 WHERE id = 1; UPDATE account SET balance = balance + 100 WHERE id = 2; COMMIT;
Conclusion: MySQL is a powerful database management system. Through the study and practice of this article, I hope readers can master the basic operations and operations of MySQL. Some advanced usage. Continuing to learn MySQL in depth and applying these skills in actual projects will help you achieve better results in the field of database development.
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