SQL Query Portfolio Project

Enhanced SQL Portfolio with Comprehensive COVID-19 Data Analysis

- Implemented advanced SQL queries to extract, analyze, and present COVID-19 data from multiple perspectives.
- Demonstrated proficiency in using WHERE clauses for data filtering based on specific criteria, such as non-null continents and minimum case thresholds.
- Showcased ability to calculate and interpret complex metrics, including total cases vs. total deaths, mortality rates, infection rates versus population, and vaccination progress.
- Utilized aggregate functions (SUM, MAX) and mathematical operations to derive insights such as death percentages, highest infection counts, and vaccination percentages.
- Employed JOIN operations to integrate COVID-19 death and vaccination datasets, enabling a comprehensive analysis of pandemic trends by location and date.
- Applied window functions with PARTITION BY and ORDER BY clauses for detailed time-series analysis, including rolling vaccination counts.
- Introduced Common Table Expressions (CTEs) and temporary tables for efficient data management and querying, illustrating advanced SQL data structuring techniques.
- Created a view for convenient re-use and visualization of critical vaccination progress data across different geographies.
- Enhanced query readability and maintainability through meticulous formatting and consistent use of aliases, contributing to best practices in SQL development.

This update enriches the SQL GitHub Portfolio with in-depth COVID-19 data exploration, reflecting a deep understanding of SQL query crafting, data analysis, and database management skills.

SQLQueryCovidDataCleaningPortfolio.sql

@@ -0,0 +1,279 @@
+
+SELECT *
+FROM 
+	dbo.CovidDeaths
+WHERE 
+	continent is not null
+order by 
+	3,4
+
+SELECT 
+	location, 
+	date, 
+	total_cases, 
+	new_cases, 
+	total_deaths, 
+	population
+FROM
+	dbo.CovidDeaths
+ORDER BY 
+	1,2
+
+-- Looking at Total Cases vs. Total Deaths
+-- Death Rate by country if you get covid
+
+SELECT 
+	location, 
+	date, 
+	total_cases, 
+	total_deaths, 
+	ROUND((total_deaths/total_cases) * 100, 2) as DeathPercentage
+FROM 
+	PortfolioProject.dbo.CovidDeaths
+WHERE 
+	location like '%Sweden%'
+ORDER BY 
+	2
+
+-- Highest Mortality rate per country with over 500 cases
+
+SELECT 
+	location, 
+	MAX(ROUND((total_deaths/total_cases) * 100, 2)) as DeathPercentage
+FROM 
+	PortfolioProject.dbo.CovidDeaths
+WHERE 
+	total_cases > '500'
+GROUP BY 
+	location
+ORDER BY 
+	DeathPercentage DESC
+
+-- Average Mortality rate --
+
+SELECT 
+	location, 
+	MAX(ROUND((total_deaths/total_cases) * 100, 2)) as DeathPercentage
+FROM 
+	PortfolioProject.dbo.CovidDeaths
+WHERE 
+	total_cases > 500
+GROUP BY 
+	location
+ORDER BY 
+	DeathPercentage DESC
+-------------------------------------------------
+
+-- Looking at countries with the highest infection rate vs. population
+SELECT 
+	location as Country, 
+	population as CountryPopulation, 
+	MAX(total_cases) AS HighestConcurrentInfectionCount, 
+	ROUND(MAX((total_cases/population)) * 100,2) AS HighestPercentPopulationInfected
+FROM 
+	PortfolioProject.dbo.CovidDeaths
+GROUP BY 
+	location, 
+	population
+ORDER BY 
+	HighestPercentPopulationInfected DESC
+
+-- Showing the countries with the highest death count per population---------
+SELECT 
+	location as Country, 
+	population as CountryPopulation, 
+	MAX(CAST(total_deaths as int)) AS TotalDeathCount
+FROM 
+	PortfolioProject.dbo.CovidDeaths
+WHERE 
+	continent is not null
+GROUP BY 
+	location, 
+	population 
+ORDER BY 
+	TotalDeathCount desc
+
+
+-- By continent | Correct
+
+SELECT 
+	location, 
+	MAX(CAST(total_deaths as int)) AS TotalDeathCount
+FROM 
+	PortfolioProject.dbo.CovidDeaths
+WHERE 
+	continent is null
+GROUP BY 
+	location
+ORDER BY 
+	TotalDeathCount desc
+
+-- Showing the continents with the highest death count
+SELECT 
+	continent, 
+	MAX(CAST(total_deaths as int)) AS TotalDeathCount
+FROM 
+	PortfolioProject.dbo.CovidDeaths
+WHERE 
+	continent is not null
+GROUP BY 
+	continent
+ORDER BY 
+	TotalDeathCount desc
+
+-- GLOBAL NUMBERS
+SELECT 
+	date, 
+	SUM(new_cases) As 'Total Cases', 
+	SUM(CAST(new_deaths AS INT)) as 'Total Deaths', 
+	ROUND(SUM(CAST(new_deaths AS INT)) / SUM(new_cases) * 100, 2) as DeathProcentage
+FROM 
+	PortfolioProject.dbo.CovidDeaths
+WHERE 
+	continent is not null AND new_cases is not null
+GROUP BY 
+	date
+ORDER BY
+	1,2 ASC
+
+SELECT
+	SUM(new_cases) As 'Total Cases', 
+	SUM(CAST(new_deaths AS INT)) as 'Total Deaths', 
+	ROUND(SUM(CAST(new_deaths AS INT)) / SUM(new_cases) * 100, 2) as DeathProcentage
+FROM 
+	PortfolioProject.dbo.CovidDeaths
+WHERE 
+	continent is not null 
+ORDER BY 
+	1,2 ASC
+
+-- JOINING the vaccination table on Sweden
+
+SELECT 
+	* 
+FROM 
+	PortfolioProject.dbo.CovidDeaths as da
+JOIN 
+	PortfolioProject.dbo.CovidVaccinations as vac on da.location = vac.location
+	AND da.date = vac.date
+WHERE 
+	da.location like '%Sweden%'
+
+--DISPLAY Vaccinations by location on dates with population
+
+SELECT 
+	da.continent, 
+	da.location, 
+	da.date, 
+	da.population, 
+	vac.new_vaccinations
+FROM
+	PortfolioProject.dbo.CovidDeaths as da
+JOIN 
+	PortfolioProject.dbo.CovidVaccinations as vac 
+	ON da.location = vac.location
+	AND da.date = vac.date
+WHERE 
+	da.continent is not null
+ORDER BY 
+	2,3
+
+-- Add rolling counter using partition by ordering by date and location
+
+SELECT 
+	da.continent, 
+	da.location, 
+	da.date, 
+	da.population, 
+	vac.new_vaccinations, 
+	SUM(CAST(vac.new_vaccinations as int)) OVER (Partition by da.location Order By da.location, da.date) as RollingVaccinationCounter
+FROM 
+	PortfolioProject.dbo.CovidDeaths as da
+JOIN 
+	PortfolioProject.dbo.CovidVaccinations AS vac 
+	ON da.location = vac.location
+	AND da.date = vac.date
+WHERE 
+	da.continent is not null
+ORDER BY 
+	2,3
+
+
+--USING CTE
+WITH PopvsVac (Continent, Location, Date, Population, New_vaccinations, RollingPeopleVaccinated) AS
+(
+    SELECT 
+        da.continent, 
+        da.location, 
+        da.date, 
+        da.population, 
+        vac.new_vaccinations, 
+        SUM(CAST(vac.new_vaccinations AS INT)) OVER (PARTITION BY da.location ORDER BY da.location, da.date) AS RollingVaccinationCounter
+    FROM 
+        PortfolioProject.dbo.CovidDeaths AS da
+    JOIN 
+        PortfolioProject.dbo.CovidVaccinations AS vac ON da.location = vac.location AND da.date = vac.date
+    WHERE 
+        da.continent IS NOT NULL
+)
+SELECT 
+    *,
+	ROUND((RollingPeopleVaccinated/Population)*100,2) as RollingProcentage
+FROM 
+    PopvsVac
+
+-- TEMP TABLE
+
+DROP TABLE IF EXISTS #PercentPopulationVaccinated
+CREATE TABLE #PercentPopulationVaccinated
+(
+	Continent nvarchar(255),
+	Location nvarchar(255),
+	Date datetime,
+	Population numeric,
+	New_vaccinations numeric,
+	RollingPeopleVaccinated numeric
+)
+
+
+INSERT INTO #PercentPopulationVaccinated
+SELECT 
+	da.continent, 
+	da.location, 
+	da.date, 
+	da.population, 
+	vac.new_vaccinations, 
+	SUM(CAST(vac.new_vaccinations as int)) OVER (Partition by da.location Order By da.location, da.date) as RollingVaccinationCounter
+FROM 
+	PortfolioProject.dbo.CovidDeaths as da
+JOIN 
+	PortfolioProject.dbo.CovidVaccinations as vac on da.location = vac.location
+	and	
+	da.date = vac.date
+WHERE 
+	da.continent is not null
+
+SELECT *, (RollingPeopleVaccinated/Population)*100
+FROM #PercentPopulationVaccinated
+
+
+-- Creating view to store data for later visualizations
+
+CREATE VIEW PercentPopulationVaccinated 
+AS
+SELECT 
+	da.continent, 
+	da.location, 
+	da.date, 
+	da.population, 
+	vac.new_vaccinations, 
+	SUM(CAST(vac.new_vaccinations as int)) OVER (Partition by da.location Order By da.location, da.date) as RollingVaccinationCounter
+FROM 
+	PortfolioProject.dbo.CovidDeaths as da
+JOIN 
+	PortfolioProject.dbo.CovidVaccinations AS vac 
+	ON da.location = vac.location
+	AND da.date = vac.date
+WHERE 
+	da.continent is not null
+---- ORDER BY 2,3