MySQL Introduction.
1. What is MySQL?
MySQL is an open-source Relational Database Management System (RDBMS) used to store, manage, and retrieve data.
It uses SQL (Structured Query Language) to interact with databases.
2. Features of MySQL
- Open-source and free
- Fast and reliable
- Supports large databases
- Works with PHP, Python, Java, and more
- Secure and scalable
3. Database Basics
- Database: Collection of related data
- Table: Data arranged in rows and columns
- Row: A single record
- Column: A data field
4. Creating a Database
CREATE DATABASE school;
5. Selecting a Database
USE school;
6. Creating a Table
CREATE TABLE students (
id INT PRIMARY KEY,
name VARCHAR(50),
age INT,
marks INT
);
7. Inserting Data
INSERT INTO students VALUES
(1, 'Alice', 15, 85),
(2, 'Bob', 16, 90);
8. Viewing Data
SELECT * FROM students;
9. Using WHERE Clause
SELECT * FROM students
WHERE marks > 80;
10. Updating Data
UPDATE students
SET marks = 95
WHERE id = 2;
11. Deleting Data
DELETE FROM students
WHERE id = 1;
12. Sorting and Limiting Results
SELECT * FROM students
ORDER BY marks DESC
LIMIT 1;
13. Aggregate Functions
| Function | Description |
|---|---|
| COUNT() | Counts number of rows |
| SUM() | Adds values |
| AVG() | Calculates average |
| MAX() | Finds maximum value |
| MIN() | Finds minimum value |
14. Example of Aggregate Query
SELECT AVG(marks) FROM students;
15. Applications of MySQL
- Web applications
- School and college databases
- E-commerce websites
- Content management systems