Learn SQL - Comprehensive Course

Beginner Level

1. 1. Introduction to SQL
   • What is SQL? History and importance
   • Understanding relational databases and RDBMS concepts
   • Overview of popular RDBMS: MySQL, PostgreSQL, Oracle, SQL Server, SQLite
   • SQL syntax basics
2. 2. Basic SQL Queries
   • SELECT statement basics
   • Retrieving specific columns and rows
   • Using DISTINCT to remove duplicates
   • Sorting results with ORDER BY
   • Limiting results with LIMIT / TOP
3. 3. Filtering Data
   • Using WHERE clause
   • Comparison and logical operators
   • Using BETWEEN, IN, and LIKE
4. 4. Working with NULLs
   • Understanding NULL
   • Filtering with IS NULL and IS NOT NULL
5. 5. Functions and Expressions
   • Aggregate functions: COUNT(), SUM(), AVG()
   • Scalar functions: UPPER(), LENGTH(), NOW()
   • Using arithmetic and string operators