Level Guides Audit

Learn the very basics of SQL and how to retrieve data using SELECT statements.

Master filtering data using various conditions in the WHERE clause.

Sort your results and control pagination with ORDER BY, LIMIT, and OFFSET.

Learn COUNT, SUM, AVG, MIN, MAX and other aggregate functions for data analysis.

Group data and filter groups using GROUP BY and HAVING clauses.

Master INNER, LEFT, RIGHT, and FULL JOINs to combine data from multiple tables.

Write complex queries within queries using subqueries and nested SELECT statements.

Use string functions, date functions, and conditional logic with CASE statements.

Learn ROW_NUMBER, RANK, LEAD, LAG and other powerful window functions.

Master Common Table Expressions and write complex, readable SQL queries.

Learn to insert, update, and delete data in tables with proper syntax and safety practices.

Understand database indexes, query execution plans, and optimization techniques.

Create complex analytical queries for business intelligence and reporting.

Write reusable stored procedures and user-defined functions for complex logic.

Master database transactions, locking, and concurrent data access patterns.

Work with complex data types, JSON data, and modern database features.

Learn database design principles, normalization, and schema optimization.

Advanced performance optimization, query tuning, and scalability strategies.

Apply all SQL skills to complex, real-world business scenarios and data problems.

Master-level challenges and comprehensive interview preparation for SQL roles.

Test your wits with advanced SQL riddles focusing on optimization, lateral thinking, and best practices.

Master transforming data from rows to columns (PIVOT) and back again (UNPIVOT). Learn powerful techniques for reshaping data to create insightful, summary-style reports.