How to use CASE in Sql server

The CASE keyword is used as a conditional operator that like the functionality of an IF-THEN-ELSE statement.

Syntax:

CASE

   WHEN condition_1 THEN result_1

   WHEN condition_2 THEN result_2

   ...

   WHEN condition_n THEN result_n

   ELSE result

END

Example: 

BEGIN

DECLARE @EnumId INT= 1

      -- Declare the return variable here

      DECLARE @result VARCHAR(100)

      SET @result = (SELECT

      CASE WHEN @EnumId = 1 THEN 'Active'

             WHEN @EnumId = 2 THEN 'Deceased'

             WHEN @EnumId = 3 THEN 'Inactive'

             WHEN @EnumId = 4 THEN 'Discharged'

             ELSE

             ''

      END)       

      select  @result

END