A collection of SQL queries and tasks based on the classic Microsoft Northwind sample database. Project demonstrates various SQL skills including data retrieval, aggregation, joins, and complex analytical queries.
This repository contains SQL queries written for the Northwind database, showcasing different SQL techniques and problem-solving approaches. The Northwind database is a sample database originally created by Microsoft, containing sales data for a fictitious company called "Northwind Traders" which imports and exports specialty foods from around the world.
The Northwind database contains the following main entities:
- Customers - Customer information
- Employees - Employee details and hierarchy
- Orders - Order headers with customer and employee references
- Order Details - Line items for each order
- Products - Product catalog with categories and suppliers
- Categories - Product categories
- Suppliers - Supplier information
- Shippers - Shipping companies
├── README.md # Project documentation ├── DatabaseDiagram.png # Visual database schema ├── dataset/ # Database setup files │ └── instnwnd.sql # Microsoft's original Northwind setup script └── tasks/ # SQL queries and solutions ├── query_01_basic_selects.sql ├── query_02_joins.sql ├── query_03_aggregations.sql └── ...
- SQL Server Management Studio (SSMS) or any SQL Server compatible tool
- SQL Server (Express edition is sufficient)
- Open SQL Server Management Studio
- Run the script from
dataset/instnwnd.sqlto create and populate the Northwind database - Verify the installation by running: USE Northwind; SELECT COUNT(*) FROM Customers; -- Should return 91
The tasks/ directory contains queries organized by complexity and topic:
- Simple SELECT statements
- Filtering with WHERE clauses
- Sorting with ORDER BY
- Data type conversions
- JOIN operations (INNER, LEFT, RIGHT, FULL OUTER)
- Subqueries and CTEs
- Aggregate functions (COUNT, SUM, AVG, etc.)
- GROUP BY and HAVING clauses
- Window functions
- Complex business logic scenarios
- Performance optimization examples
- Stored procedures and functions
This project demonstrates proficiency in:
- ✅ Complex JOIN operations across multiple tables
- ✅ Aggregate functions and GROUP BY operations
- ✅ Subqueries and Common Table Expressions (CTEs)
- ✅ Window functions for analytical queries
- ✅ Data filtering and conditional logic
- ✅ Performance considerations in query writing
- ✅ Business intelligence and reporting queries
- SQL Server - Database engine
- SQL Server Management Studio (SSMS) - Query development and execution
- Microsoft Northwind Database - Sample dataset
This project is for educational purposes. The Northwind database is a Microsoft sample database available for learning and development.
Skills Demonstrated: SQL, Database Analysis, Business Intelligence, Data Retrieval, Query Optimization