Convert SQL Procedure to MYSQL procedure

CREATE PROC [dbo].[LoadData]
(
   @mode int=NULL,
   @id int=null
)
AS 
BEGIN

   IF(@mode=1)
      BEGIN
         IF(@id>0)
            BEGIN
               SELECT * FROM tbl_user Where pk_userid=@id and bActive=1
            END 
         ELSE
            BEGIN
               SELECT usr1.pk_userid, 
                      usr1.username, 
                      case usr1.roleid 
                         when 1 then 'Admin'
                         when 2 then 'User' 
                         when 3 then 'Sub User' 
                         WHEN 4 then 'Partner' 
                         else 'Super Admin' 
                      END as UserRole,
                      ISNULL(usr2.username,'') As Head 
               FROM tbl_user usr1 
               LEFT JOIN tbl_user usr2 ON usr1.headuserid=usr2.pk_userid
               WHERE usr1.bActive=1 AND usr1.roleid IN (1)
               --WHERE usr1.bActive=1 AND usr1.roleid NOT IN (5)
            END
         END
	
END