-- -- RANDOM -- Test the random function -- -- count the number of tuples originally, should be 1000 SELECT count(*) FROM onek; -- pick three random rows, they shouldn't match (SELECT unique1 AS random FROM onek ORDER BY random() LIMIT 1) INTERSECT (SELECT unique1 AS random FROM onek ORDER BY random() LIMIT 1) INTERSECT (SELECT unique1 AS random FROM onek ORDER BY random() LIMIT 1); -- count roughly 1/10 of the tuples SELECT count(*) AS random INTO RANDOM_TBL FROM onek WHERE random() < 1.0/10; -- select again, the count should be different INSERT INTO RANDOM_TBL (random) SELECT count(*) FROM onek WHERE random() < 1.0/10; -- select again, the count should be different INSERT INTO RANDOM_TBL (random) SELECT count(*) FROM onek WHERE random() < 1.0/10; -- select again, the count should be different INSERT INTO RANDOM_TBL (random) SELECT count(*) FROM onek WHERE random() < 1.0/10; -- now test that they are different counts SELECT random, count(random) FROM RANDOM_TBL GROUP BY random HAVING count(random) > 3; SELECT AVG(random) FROM RANDOM_TBL HAVING AVG(random) NOT BETWEEN 80 AND 120;