📘 Data Technician Workbook - SQL | Just IT's Data Skills Bootcamp (PDF)

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🗂️ Overview

This repository contains my completed SQL workbook from Just IT's Data Skills Bootcamp. It demonstrates my understanding of SQL concepts, relational databases, and practical SQL querying techniques using a real-world dataset.

The workbook includes research-based theory, hands-on exercises using the world_db sample dataset, and a final applied project that simulates building a database for a small retail business.

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📌 Topics Covered

🧠 Theory-Based SQL & Database Fundamentals

• Primary Keys vs. Foreign Keys
• One-to-One, One-to-Many, and Many-to-Many Relationships
• Relational vs. Non-Relational Databases
• Use cases for different database types

🔗 SQL JOIN Types

• INNER JOIN
• LEFT JOIN
• RIGHT JOIN
• FULL OUTER JOIN
• SELF JOIN
• CROSS JOIN

Each join is explained with definitions, real-world applications, and example SQL syntax.

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🧪 Practical SQL Tasks (Using world_db)

Real-world scenario-based SQL queries using a sample database:

Task	Description
✅ Count cities in the USA	Basic COUNT query
🌍 Country with highest life expectancy	Using MAX()
🗺️ Cities with "New" in the name	LIKE clause usage
🔢 Top 10 most populous cities	ORDER BY with LIMIT
🧮 Cities with population > 2M	WHERE filtering
📜 Cities starting with "Be"	Pattern matching
📊 Cities with mid-range population	BETWEEN clause
🔠 Cities sorted by name	Alphabetical sorting
🏙️ Most and least populated cities	MAX() and MIN()
🔁 City name frequency count	GROUP BY and COUNT()
🌐 Country with highest population	Aggregation queries
🇪🇸 Capital city of Spain	Simple WHERE clause
🇪🇺 List of European cities	Region filtering
👥 Average population by country	GROUP BY with AVG()
🏙️ Capital cities population comparison	Advanced joins
🌾 Countries with low population density	Custom metrics
💰 Cities with high GDP per capita	Economic analysis
📉 Cities ranked 31–40 by population	Pagination with LIMIT & OFFSET

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🧱 Final Written Project

Title: Designing and Implementing a SQL Database for a Small Retail Business

A 500-word essay and SQL implementation covering:

• Identifying business requirements for inventory, sales, and customer tracking
• Database schema design with appropriate relationships
• SQL scripts to create tables (CREATE TABLE, FOREIGN KEY)
• Sample INSERT statements for test data
• SQL-based security & backup practices (GRANT, mysqldump)

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🛠️ Tools & Technologies

• SQL client tools: MySQL Workbench
• world_db sample dataset
• Power Query Editor (for review)

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✅ Learning Outcomes

By completing this workbook, I developed proficiency in:

• Writing accurate SQL queries for analysis and reporting
• Understanding relational database design
• Solving practical business problems using SQL
• Communicating technical solutions clearly