Select EmployeeID, JobTitle, Salary

From EmployeeSalary

Select EmployeeID, Salary, (Select AVG(Salary) From EmployeeSalary) as AllAvgSalary

From EmployeeSalary

Select EmployeeID, Salary, AVG(Salary) over () as AllAvgSalary

From EmployeeSalary

Select EmployeeID, Salary, AVG(Salary) as AllAvgSalary

From EmployeeSalary

Group By EmployeeID, Salary

order by EmployeeID

Select a.EmployeeID, AllAvgSalary

From

(Select EmployeeID, Salary, AVG(Salary) over () as AllAvgSalary

From EmployeeSalary) a

Order by a.EmployeeID

Select EmployeeID, JobTitle, Salary

From EmployeeSalary

where EmployeeID in (

Select EmployeeID

From EmployeeDemographics

where Age > 30)