Is there any other example to understand keyword "as"

Answer 1

Ex: Table Name Student

Table contains columns StudentID and StudentName

Select StudentID, StudentName from Student ;

result you see as:

StudentID StudentName
1 x

using As Keyword

Select StudentID, StudentName as EmployeeName from Student ;

then u see result as:

StudentId EmployeeName
1 x

Answer 2

as keywords referencing alias name ...
select ID as Employee_ID from emp