T-SQL Merge Example using a value pair

merge W_Entity_Pool
          using ( SELECT 58 AS entity_typ_cd) AS A
                  ON A.entity_typ_cd = W_Entity_Pool.entity_typ_cd

when matched then
update set pool_seq_num = 5

when not matched then
INSERT(entity_typ_cd,DATA_DOMAIN_ID, pool_seq_num)
values(58,1,5);