Become a data scientist

Combine multiple tables using various JOIN types to construct comprehensive business reports.

Apply CASE statements and Common Table Expressions (CTEs) to implement complex business logic and structure analytical queries.

Utilize window functions (e.g., PARTITION BY, RANK(), DENSE_RANK()) to perform partitioned analysis, such as ranking customers by sales within regions.

Calculate running totals and moving averages using window functions with a frame clause to analyze trends.

Perform time-based aggregations (e.g., daily, monthly) to create time-series business metrics.

Write a SQL query to structure a cohort analysis for calculating user retention.

Handle NULL values in analytical queries using functions like COALESCE and NULLIF to ensure accurate aggregations.

Rewrite subqueries as CTEs or JOINs to improve query readability and maintainability for analytical tasks.