Hi every one.
i created this trigger

create trigger dec_num
after insert on sales
For each row mode db2sql
update product set pro_qty = pro_qty - 1
where EXISTS (select product.pro_id from sales,product where product.pro_id = sales.pro_id);

insert into sales values ('s1',1.34,'2010-8-1','m1','p1h1','h1');

after insert data into sales table all pro_qty form product table decrement by 1

Please supply DDLs of product and sales and sample data of product.

You posted recently another two questions, right?

I guessed that all three questions are related to an requirement.

If so, please describe your concrete requirements without using SQL statements like "UPDATE product ..." / "CREATE trigger ...".

Hi . i have to table sales and product . table product has field pro_id and pro_name and pro_qty ,and table sales has sal_id and pro_id(foreign key) . i want pro_qty in table product decrement by one when one item insert into table sales.

if I buy 2 or more of an item, do you put 2 or more rows into sales? or do you have a quantity filed?

yes. put 2 or more rows into sales

quantity filed exists in table product