create trigger tr_ins_opera on opera
instead of insert
as
begin
    if exists (select 1 from inserted where mark='取款')
    begin
        if exists (select 1 from inserted a inner join uesr b on a.id = b.id and a.mark='取款' and a.change>b.money)
        begin
            print '超出取款金额'
            rollback tran
        end
        
        update uesr set money = money - change
        from uesr a inner join inserted b on a.id = b.id and b.mark='取款'
    
    end
    
    if exists (select 1 from inserted where mark='存款' )
    begin
        update uesr set money = money + change
        from uesr a inner join inserted b on a.ID = b.id and b.mark='存款'
        
    end
end

------解决方案--------------------

SQL code
create trigger t1
on opera
for insert
as
begin
   declare @s varchar(10),@t int 
   select @s=mark from inserted
   if(@s='取款')
   begin
     if not exists(select 1 from user join inserted on user.id=inserted.id and money>change)
        rollback
    else
        update user
        set money=money-change
        from user join inserted on user.id=inserted.id 
   end
   else
        update user
        set money=money+change
        from user join inserted on user.id=inserted.id 
end