Data Analysis Portfolio 🚀

A collection of SQL and data analysis projects showcasing skills in data cleaning, exploration, and visualization. This repository serves as a portfolio to demonstrate proficiency in deriving insights from raw datasets.

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📋 Project Overview

This repository contains multiple data analysis projects, each focusing on different datasets and analytical techniques. Key highlights include:

• Data Cleaning: Standardization, deduplication, and handling missing values.
• Exploratory Data Analysis (EDA): Trend identification, aggregation, and statistical summaries.
• Advanced Queries: Window functions, CTEs, and time-series analysis.
• Visualizations: Results formatted for dashboards or reporting.

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🛠️ Key Features

1. Analyses Included

Project Name	Description	Tools Used
WorldLayoffs	Analysis of global layoffs trends (Example: companies, industries, countries).	MySQL
UnicornCompanies	Analysis per industry, country and funding of unicorn companies.	MySQL
311ServiceRequestsCalgary	Temporal, Service Type Analyses and Geographical Distribution Visualization	Excel, MySQL

2. Core Techniques

• Data Cleaning:
  • Deduplication using ROW_NUMBER() and CTEs.
  • Standardization of categorical values (e.g., industries, countries).
  • Date formatting and NULL handling.
• Aggregation:
  • SUM(), AVG(), and window functions (OVER(), PARTITION BY).
  • Rolling totals and cumulative metrics.
• Ranking:
  • DENSE_RANK() for top-N queries (e.g., "Top 5 Companies by Layoffs").

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🚀 Setup Instructions

1. Clone the Repository:

   git clone https://github.com/GYahia/MySQL.git
   

2. Database Setup:

• Import datasets into MySQL using Workbench or CLI:

  CREATE DATABASE [database_name];
  USE [database_name];
  -- Import CSV via MySQL Workbench's Table Data Import Wizard.

3. Run Queries:

• Execute SQL scripts (e.g., world_layoffs.sql) to replicate cleaning and analysis steps.

📊 Example Queries

1. Top 5 Industries by Layoffs (SQL)

   SELECT industry, SUM(total_laid_off) AS total_laid_off
   FROM layoffs_clean_v2
   GROUP BY industry
   ORDER BY total_laid_off DESC
   LIMIT 5;

2. Yearly Layoff Trends

   SELECT YEAR(date) AS year, SUM(total_laid_off) AS total_laid_off
   FROM layoffs_clean_v2
   GROUP BY YEAR(date)
   ORDER BY year;

3. Average Reponse Time per Community after reduction to unique requests

   WITH UniqueRequests AS (
      SELECT DISTINCT requested_date,
             closed_date,
             point,
             service_name,
             comm_name,
             MIN(response_time_days) AS response_time_days
      FROM service_requests_clean_v3
      GROUP BY requested_date,
             closed_date,
             point,
             service_name,
             comm_name)
   SELECT comm_name,
      ROUND(AVG(response_time_days), 0) AS avg_response_time,
      (
             SELECT ROUND(AVG(response_time_days), 0)
             FROM UniqueRequests
      ) AS avg_overall,
      FROM UniqueRequests
   GROUP BY comm_name
   ORDER BY avg_response_time DESC;

🔧 Future Enhancements

• Add interactive dashboards (e.g., Tableau/Power BI).
• Integrate Python scripts for automated data cleaning.
• Expand analysis to include macroeconomic factors (e.g., GDP, inflation).

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