If OBJECT_ID('usp_Cau11','p') is not null
    drop proc usp_Cau11
go
create proc usp_Cau11
@mapm char(10),
@ngaymuon date
as
    if not exists(select * from PhieuMuon where mapm= @mapm) return 1

    Update PhieuMuon
    set ngaymuon = @ngaymuon
    where mapm= @mapm

    update ctpt
    set tienphat =
         IIF(ctpt.mucgiaphat*(DATEDIFF(DD,pm.ngaymuon, pt.ngaytra)-ctpm.songayquydinh)>=0,ctpt.mucgiaphat*(DATEDIFF(DD,pm.ngaymuon, pt.ngaytra)-ctpm.songayquydinh),0)
    from PhieuMuon pm join PhieuTra pt on (pm.mapm = pt.mapm) join CT_PhieuTra ctpt on (pt.mapt= ctpt.mapt) join CT_PhieuMuon ctpm on (ctpm.mapm= pm.mapm)
    where pm.mapm = @mapm

    if @@ROWCOUNT >0 return 0
go
/*
select * from CT_PhieuTra
select * from PhieuMuon
select * from CT_PhieuMuon
select * from PhieuTra
*/
exec usp_Cau11 N'PM001',N'1/16/2014'