performance question

What will be better?

UPDATE table1

SET         table1.some_col =
          (SELECT some_col FROM table2
                     WHERE table2.col_id = table1.col_id)
WHERE EXISTS
        (SELECT null FROM table2
                     WHERE table2.col_id = table1.col_id)

or:

CREATE VIEW my_view AS SELECT table1.some_col c1, table2.some_col c2

            WHERE table1.col_id = table2.col_id

UPDATE my_view SET c1 = c2 Received on Tue Feb 08 2005 - 14:02:19 CST