175658630409872728_SQL_Presentation.pptx

Sql

1. Introduction to SQL Structured Query Language Basics

2. What is SQL? • SQL stands for Structured Query Language • Used to communicate with databases • SQL is the standard language for Relational Database Management Systems (RDBMS) • Examples: MySQL, PostgreSQL, Oracle, SQL Server

3. Basic SQL Commands • SELECT – retrieve data from a database • INSERT – add new data • UPDATE – modify existing data • DELETE – remove data • CREATE – create new tables/databases • DROP – delete tables/databases

4. SELECT Statement • Used to retrieve data from one or more tables • Syntax: SELECT column1, column2 FROM table_name WHERE condition; • Example: SELECT name, age FROM students WHERE age > 18;

5. Filtering Data with WHERE • WHERE clause filters records • Operators: =, >, <, >=, <=, <>, LIKE, IN, BETWEEN • Example: SELECT * FROM employees WHERE salary > 50000;

6. Sorting and Limiting Data • ORDER BY – sort results (ASC/DESC) • LIMIT – restrict number of rows returned • Example: SELECT * FROM products ORDER BY price DESC LIMIT 5;

7. Joins in SQL • JOIN is used to combine rows from two or more tables • Types of joins: – INNER JOIN – LEFT JOIN – RIGHT JOIN – FULL OUTER JOIN • Example: SELECT students.name, courses.course_name FROM students INNER JOIN courses ON students.course_id = courses.id;

8. Aggregate Functions • Used to perform calculations on data • Common functions: – COUNT() – SUM() – AVG() – MIN() – MAX() • Example: SELECT AVG(salary) FROM employees;

9. Conclusion • SQL is essential for managing and manipulating data • Provides commands for querying, inserting, updating, and deleting data • Widely used in databases like MySQL, PostgreSQL, Oracle, and SQL Server