How can I insert the return of DELETE into INSERT in postgresql?

You cannot do this before PostgreSQL 9.1, which is not yet released. And then the syntax would be

WITH foo AS (DELETE FROM a WHERE id = 1 RETURNING one, two, 5)    INSERT INTO b (one, two, num) SELECT * FROM foo;

Before PostgreSQL 9.1 you can create a volatile function like this (untested):

create function move_from_a_to_b(_id integer, _num integer)returns void language plpgsql volatile as$$  declare    _one integer;    _two integer;  begin    delete from a where id = _id returning one, two into strict _one, _two;    insert into b (one,two,num) values (_one, _two, _num);  end;$$

And then just use select move_from_a_to_b(1, 5). A function has the advantage over two statements that it will always run in single transaction — there's no need to explicitly start and commit transaction in client code.

For all version of PostgreSQL, you can create a trigger function for deleting rows from a table and inserting them to another table. But it seems slower than bulk insert that is released in PostgreSQL 9.1. You just need to move the old data into the another table before it gets deleted. This is done with the OLD data type:

CREATE FUNCTION moveDeleted() RETURNS trigger AS $$    BEGIN        INSERT INTO another_table VALUES(OLD.column1, OLD.column2,...);        RETURN OLD;    END;$$ LANGUAGE plpgsql;CREATE TRIGGER moveDeletedBEFORE DELETE ON table     FOR EACH ROW        EXECUTE PROCEDURE moveDeleted();

As above answer, after PostgreSQL 9.1 you can do this:

WITH tmp AS (DELETE FROM table RETURNING column1, column2, ...)    INSERT INTO another_table (column1, column2, ...) SELECT * FROM tmp;