Insert, on duplicate update in PostgreSQL?

Question

Several months ago I learned from an answer on Stack Overflow how to perform multiple updates at once in MySQL using the following syntax:

INSERT INTO table          


        

Answer 1

Similar to most-liked answer, but works slightly faster:

WITH upsert AS (UPDATE spider_count SET tally=1 WHERE date='today' RETURNING *)
INSERT INTO spider_count (spider, tally) SELECT 'Googlebot', 1 WHERE NOT EXISTS (SELECT * FROM upsert)

(source: http://www.the-art-of-web.com/sql/upsert/)