Learn SQL

SQL Topics

Click on a topic to expand and learn in detail.

• 1. Introduction to SQL

-- SQL (Structured Query Language) is used to manage databases
SELECT * FROM Students;
      

• 2. Data Manipulation (DML)

INSERT INTO Students(Name, Age) VALUES('Alice', 25);
UPDATE Students SET Age = 26 WHERE Name = 'Alice';
DELETE FROM Students WHERE Age < 18;
SELECT * FROM Students;
      

• 3. Data Definition (DDL)

CREATE TABLE Students(
    ID INT PRIMARY KEY,
    Name VARCHAR(50),
    Age INT
);
ALTER TABLE Students ADD COLUMN Grade CHAR(1);
DROP TABLE OldStudents;
      

• 4. Advanced SQL
• JOINs (INNER, LEFT, RIGHT, FULL)
• GROUP BY, HAVING
• Aggregate Functions (COUNT, SUM, AVG)
• Subqueries
• Views
• Indexes