Case statements in SQL

Case Statements in SQL :
Can be used  in select,insert,update and delete .
>>Case input expression
       when when_expression then resule expression
       [else else_result_expression]
  End

SELECT EmployeeId
 ,EName
 ,Ecity
 ,CASE Ecity
  WHEN 'Delhi'
   THEN 'DELHI'
  ELSE 'NOT_DELHI'
  END isDelhi
FROM Employees
ORDER BY
 ,Ename
 ,EmployeeID;

--So in the above example we sort of created a binary variable for a categorical variable.

SELECT EmployeeId
 ,EName
 ,ESex CASE ESex
  WHEN 'Female'
   THEN '1'
  ELSE '0'
  END Coded_sex
FROM Employees
ORDER BY Ename
 ,EmployeeID;

--Seach Case Statement 

SELECT trackid
 ,name
 ,bytes
 ,CASE 
  WHEN BYTES < 300000
   THEN 'small'
  WHEN BYTES >= 300001
   AND BYTES <= 500000
   THEN 'medium'
  ELSE 'large'
  END BYTE_SIZE
FROM tracks;