A collection of advanced SQL exercises demostrating data cleaning, transformation, and analytical skills using NULL functions, date operations, and aggregations.
Overview: This repository contains a collection of advanced SQL exercises designed to strengthen data analysis and querying skills. The focus is on handling real-world data scenarios such as missing values, date manipulation, and data aggregation.
Objectives: • Practice advanced SQL concepts • Improve problem-solving using data • Prepare for technical interviews and real-world data tasks • Build a strong portfolio for data analyst/data scientist roles
Tools & Technologies • SQL (Databricks ) • GitHub for version control
Example Topics • Replacing NULL values with default values • Calculating time differences between dates • Filtering grouped data using HAVING • Combining multiple tables using joins
These exercises demonstrate practical SQL techniques commonly used in data analytics and data science roles.
Skills Covered
- NULL handling (COALESCE, IS NULL, NULLIF)
- Date functions (DATE, DATEDIFF, EXTRACT, CURRENT_DATE)
- Aggregations (SUM, COUNT, AVG, GROUP BY, HAVING)
- Joins (INNER JOIN, LEFT JOIN, etc.)
- Data filtering and transformation
- Writing clean and efficient SQL queries