SQL/challenge-009/3.2.sql at main · wmdev0808/SQL · GitHub

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USE Animal_Shelter; -- For SQL Server

-- Dealing with NULLs
SELECT	Species,
		Breed,
		COUNT(*) AS Number_Of_Animals
FROM	Animals
GROUP BY Species, Breed;

SELECT	YEAR(Birth_Date) AS Year_Born,
		COUNT(*) AS Number_Of_Persons
FROM	Persons
GROUP BY YEAR(Birth_Date);

SELECT	YEAR(CURRENT_TIMESTAMP) - YEAR(Birth_Date) AS Age,
		COUNT(*) AS Number_Of_Persons
FROM	Persons
GROUP BY YEAR(Birth_Date);

SELECT	City,
		MIN(YEAR(CURRENT_TIMESTAMP) - YEAR(Birth_Date)) AS Oldest_Person,
		MAX(YEAR(CURRENT_TIMESTAMP) - YEAR(Birth_Date)) AS Youngest_Person,
		COUNT(*) AS Number_Of_Persons
FROM	Persons
GROUP BY City;

-- Eliminating duplicates
SELECT	Species,
		Name
FROM	Vaccinations;

SELECT	Species,
		Name
FROM	Vaccinations
GROUP BY Species, Name;

SELECT	DISTINCT
		Species,
		Name
FROM	Vaccinations;

SELECT	DISTINCT Species,
		Name,
		COUNT(*) AS  Number_Of_Vaccines
FROM	Vaccinations; /*Invalid*/

SELECT	Species,
		--Name,
		COUNT(*) AS Number_Of_Vaccines
FROM	Vaccinations
GROUP BY Species, Name
ORDER BY Species, Number_Of_Vaccines;

SELECT	DISTINCT
		Species,
		--Name,
		COUNT(*) AS Number_Of_Vaccines
FROM	Vaccinations
GROUP BY Species, Name
ORDER BY Species, Number_Of_Vaccines;