Please try this :
use tempdb -- for testing
go
create table dbo.bid ( aut_id int primary key, bid_price money )
create table dbo.aut_attr ( aut_id int primary key, min_bid_price money )
go
insert dbo.aut_attr values ( 1,100 )
insert dbo.aut_attr values ( 2,200 )
insert dbo.aut_attr values ( 3,300 )
insert dbo.aut_attr values ( 4,400 )
go
create trigger bid_ins
on dbo.bid
for insert, update
as
begin
if exists ( select 1 from inserted I, dbo.aut_attr A where I.aut_id = A.aut_id and I.bid_price < A.min_bid_price )
begin
RAISERROR ('bid_price should be >= min_bid_price', 16, 1)
rollback transaction
end
end
go