SQL/Join data at main · santanudeb/SQL · GitHub

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xxx==============================================================================================================xxx

[Notes - For joining two table with common row, here it's EmployeeID]

SELECT * FROM EmployeeDemographics
INNER JOIN EmployeeSalary
 ON EmployeeDemographics.EmployeeID = EmployeeSalary.EmployeeID
;

xxx==============================================================================================================xxx

[Notes - For joining two table with common row, here it's EmployeeID]

SELECT * FROM EmployeeDemographics AS DEM
INNER JOIN EmployeeSalary AS EMS
 ON DEM.EmployeeID = EMS.EmployeeID
;

xxx==============================================================================================================xxx

[Notes - For joining two table with common row, here it's EmployeeID]

SELECT DEM.Age, Gender, Salary
FROM EmployeeDemographics AS DEM
INNER JOIN EmployeeSalary AS EMS
 ON DEM.EmployeeID = EMS.EmployeeID
;

xxx==============================================================================================================xxx

[Notes - RIGHT JOIN is taking everything from right table and matching it with the left table]

SELECT *
FROM EmployeeDemographics AS DEM
RIGHT JOIN EmployeeSalary AS EMS
 ON DEM.EmployeeID = EMS.EmployeeID
;

xxx==============================================================================================================xxx

[Notes - LEFT JOIN is taking everything from left table and matching it with the left table]

SELECT *
FROM EmployeeDemographics AS DEM
LEFT JOIN EmployeeSalary AS EMS
 ON DEM.EmployeeID = EMS.EmployeeID
;

xxx==============================================================================================================xxx

[Notes - LEFT JOIN is taking everything from left table and matching it with the left table]

SELECT *
FROM EmployeeSalary AS emp1
JOIN EmployeeSalary AS emp2
 ON emp1.EmployeeID + 1 = emp2.EmployeeID
;

xxx==============================================================================================================xxx

[Notes - LEFT JOIN is taking everything from left table and matching it with the left table]

SELECT emp1.EmployeeID as emp_santa,
emp1.FirstName as FirstName_santa,
emp2.EmployeeID as emp_santa,
emp2.FirstName as FirstName_santa
FROM EmployeeDemographics AS emp1
JOIN EmployeeDemographics AS emp2
 ON emp1.EmployeeID + 1 = emp2.EmployeeID
;