[SQL] Creating a field that uses totals other fields?

I am wanting to create a table that will sum up the total of an order and automatically put value in the specified field. An example of the table is below. Any ideas on how to do this. CREATE TABLE sales_info ( sales_id serial PRIMARY KEY, prod_id int REFERENCES product (prod_id), qty int, uni

[SQL] Displaying current queries on the database?

I was wondering if there is a way to display all of the current queries that are being submitted to the database. Thanks in advance. -Sloan Bowman ---(end of broadcast)--- TIP 4: Don't 'kill -9' the postmaster