📊 SQL Fundamentals
Master the essential SQL skills needed for data engineering, from basic queries to advanced techniques.
Level:
Beginner to Intermediate
Tools:
PostgreSQL
MySQL
SQLite
BigQuery
Snowflake
Skills You'll Learn:
Query writing
Data filtering
Joins
Aggregations
Window functions
Step 1: Basic SQL Queries
- 1Learn SELECT, FROM, and WHERE clauses
- 2Practice filtering data with comparison operators
- 3Use LIKE and wildcards for pattern matching
- 4Sort results with ORDER BY
- 5Limit results with LIMIT and OFFSET
Step 2: Data Aggregation
- 1Use COUNT, SUM, AVG, MIN, MAX functions
- 2Group data with GROUP BY
- 3Filter groups with HAVING
- 4Understand NULL values and handling
Step 3: Joins and Relationships
- 1Master INNER JOIN
- 2Learn LEFT, RIGHT, and FULL OUTER JOINs
- 3Practice CROSS JOIN and SELF JOIN
- 4Work with multiple table joins
Step 4: Advanced Techniques
- 1Use subqueries and CTEs (Common Table Expressions)
- 2Learn window functions (ROW_NUMBER, RANK, LAG, LEAD)
- 3Practice CASE statements for conditional logic
- 4Use UNION and INTERSECT for combining results
Step 5: Data Modification
- 1Insert data with INSERT INTO
- 2Update existing records with UPDATE
- 3Delete records with DELETE
- 4Use transactions for data integrity
Step 6: Database Design Basics
- 1Understand primary and foreign keys
- 2Learn about indexes and performance
- 3Practice normalization concepts
- 4Create and modify table structures