SQL-For-Absulate-Beginners-Easy-Like-a-Cake

SQL-Basics.sql

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+-- SQL Basics: Creating Tables, Inserting Data, and Retrieving Data
+
+-- 1. Creating EmployeeDemographics Table
+-- This creates a table to store employee demographic information, such as EmployeeID, Name, Age, and Gender.
+CREATE TABLE EmployeeDemographics (
+    EmployeeID INT PRIMARY KEY,
+    FirstName VARCHAR(50),
+    LastName VARCHAR(50),
+    Age INT,
+    Gender VARCHAR(50)
+);
+
+-- 2. Creating EmployeeSalary Table
+-- This creates a table to store employee salary information, linked to EmployeeDemographics through EmployeeID.
+CREATE TABLE EmployeeSalary (
+    EmployeeID INT PRIMARY KEY,
+    JobTitle VARCHAR(50),
+    Salary INT,
+    FOREIGN KEY (EmployeeID) REFERENCES EmployeeDemographics(EmployeeID)
+);
+
+-- 3. Inserting Sample Data into EmployeeDemographics
+-- This inserts sample employee demographic data into the EmployeeDemographics table.
+INSERT INTO EmployeeDemographics (EmployeeID, FirstName, LastName, Age, Gender) VALUES
+(1001, 'Jim', 'Harper', 30, 'Male'),
+(1002, 'Emma', 'Watson', 25, 'Female'),
+(1003, 'Michael', 'Scott', 40, 'Male'),
+(1004, 'Sarah', 'Johnson', 28, 'Female'),
+(1005, 'David', 'Smith', 35, 'Male'),
+(1006, 'Laura', 'Brown', 22, 'Female');
+
+-- 4. Inserting Sample Data into EmployeeSalary
+-- This inserts sample employee salary data into the EmployeeSalary table.
+INSERT INTO EmployeeSalary (EmployeeID, JobTitle, Salary) VALUES
+(1001, 'Salesman', 45000),
+(1002, 'Manager', 60000),
+(1003, 'Engineer', 55000),
+(1004, 'Analyst', 52000),
+(1005, 'Developer', 48000),
+(1006, 'Designer', 47000);
+
+-- SQL Queries for Data Retrieval & Analysis
+
+-- 5. Selecting all data from EmployeeDemographics
+-- This query retrieves all data from the EmployeeDemographics table.
+SELECT * FROM EmployeeDemographics;
+
+-- 6. Selecting unique genders
+-- This query retrieves all unique gender values from the EmployeeDemographics table.
+SELECT DISTINCT Gender FROM EmployeeDemographics;
+
+-- 7. Counting the number of employees by gender
+-- This query counts how many employees there are for each gender.
+SELECT Gender, COUNT(Gender) AS CountGender
+FROM EmployeeDemographics
+GROUP BY Gender;
+
+-- 8. Selecting employees where age is less than or equal to 30 and gender is Male
+-- This query retrieves employees whose age is 30 or less and who are male.
+SELECT * FROM EmployeeDemographics
+WHERE Age <= 30 AND Gender = 'Male';
+
+-- 9. Ordering employees by Age (Descending) and Gender (Ascending)
+-- This query sorts employees by age in descending order and gender in ascending order.
+SELECT * FROM EmployeeDemographics
+ORDER BY Age DESC, Gender ASC;
+
+-- 10. Finding employees whose last name starts with 'S'
+-- This query retrieves employees whose last name starts with the letter 'S'.
+SELECT * FROM EmployeeDemographics
+WHERE LastName LIKE 'S%';
+
+-- 11. Finding employees whose last name contains 'S'
+-- This query retrieves employees whose last name contains the letter 'S'.
+SELECT * FROM EmployeeDemographics
+WHERE LastName LIKE '%S%';
+
+-- 12. Finding employees whose last name ends with 'S'
+-- This query retrieves employees whose last name ends with the letter 'S'.
+SELECT * FROM EmployeeDemographics
+WHERE LastName LIKE '%S';
+
+-- 13. Selecting employees with specific first names
+-- This query retrieves employees whose first names are either 'Jim' or 'Michael'.
+SELECT * FROM EmployeeDemographics
+WHERE FirstName IN ('Jim', 'Michael');