SQL_SW_CASE

    SELECT   ProductNumber, Category =  
          CASE ProductLine  
             WHEN 'R' THEN 'Road'  
             WHEN 'M' THEN 'Mountain'  
             WHEN 'T' THEN 'Touring'  
             WHEN 'S' THEN 'Other sale items'  
             ELSE 'Not for sale'  
          END,  
       Name  
    FROM Production.Product  
    GO  

• Other Example

        CREATE PROCEDURE `uspLogInMember`(
        Id int,
        SearchId int /* this param eqals to column called account in table called memeber*/
    )
    BEGIN
  
        declare checkKey varchar(20);
        set checkKey = member.Level;
  
        select checkKey =
            case member.Level
                when 0 then 'down'
                when 1 then 'downMiddleLevel'
                when 2 then 'midMiddleLevel'
                when 3 then 'upMiddleLevel'
                Else 'top'
            End, 
            m.Id, m.account
        from member as m
        where m.Id = Id and m.account = SearchId;
  
        if checkKey = 'down' then 
  
            select *
            from gmember as m 
            where m.Id = Id and gm.account = SearchId;
  
        if checkKey = 'downMiddleLevel' then
  
                select *
                from(select * from member as m where m.Id = Id) as tampTable
                where tampTable.Level = 0 or tampTable.agentLevel = 1;
  
        elseif checkKey = 'midMiddleLevel' then
  
            select *
            from(select * from member as m where m.Id = Id) as tampTable
            where tampTable.Level = 0 or tampTable.Level = 1 or  tampTable.Level = 2; 
  
        elseif checkKey = 'upMiddleLevel' then
  
            select *
            from(select * from member as m where m.Id = Id) as tampTable
            where tampTable.Level = 0 or tampTable.Level = 1 or tampTable.Level = 2 or tampTable.Level = 3;
  
  
        elseif checkKey = 'top' then 
  
            select * from member as m where gm.Id = Id;
  
        end if;
  
    END