PostgreSQL - Using a Subquery to Update Multiple Column Values

Question

I need to be able to update multiple columns on a table using the result of a subquery. A simple example will look like below -

UPDATE table1
SET (col1, col2) =         


        

Answer 1

One option (but not the only one) is to use two separate sub-queries:

update table1
set col1 = (select min(ship_charge) from orders),
    col2 = (select max(ship_charge) from orders)
where col4 = 1001;

From the fine manual for PostgreSQL 9.0's UPDATE:

According to the standard, the column-list syntax should allow a list of columns to be assigned from a single row-valued expression, such as a sub-select:

UPDATE accounts SET (contact_last_name, contact_first_name) =
(SELECT last_name, first_name FROM salesmen
 WHERE salesmen.id = accounts.sales_id);

This is not currently implemented — the source must be a list of independent expressions.