forked from huawei/openGauss-server
51 lines
1.4 KiB
SQL
51 lines
1.4 KiB
SQL
--
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-- RANDOM
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-- Test the random function
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--
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-- count the number of tuples originally, should be 1000
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SELECT count(*) FROM onek;
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-- pick three random rows, they shouldn't match
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(SELECT unique1 AS random
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FROM onek ORDER BY random() LIMIT 1)
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INTERSECT
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(SELECT unique1 AS random
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FROM onek ORDER BY random() LIMIT 1)
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INTERSECT
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(SELECT unique1 AS random
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FROM onek ORDER BY random() LIMIT 1);
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-- count roughly 1/10 of the tuples
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SELECT count(*) AS random INTO RANDOM_TBL
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FROM onek WHERE random() < 1.0/10;
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-- select again, the count should be different
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INSERT INTO RANDOM_TBL (random)
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SELECT count(*)
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FROM onek WHERE random() < 1.0/10;
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-- select again, the count should be different
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INSERT INTO RANDOM_TBL (random)
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SELECT count(*)
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FROM onek WHERE random() < 1.0/10;
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-- select again, the count should be different
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INSERT INTO RANDOM_TBL (random)
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SELECT count(*)
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FROM onek WHERE random() < 1.0/10;
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-- now test that they are different counts
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SELECT random, count(random) FROM RANDOM_TBL
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GROUP BY random HAVING count(random) > 3;
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SELECT AVG(random) FROM RANDOM_TBL
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HAVING AVG(random) NOT BETWEEN 80 AND 120;
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--disable random_function_shippable when inserting random value into a distribution column
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drop table if exists random_test;
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create table random_test (a int, b int);
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explain (verbose on, costs off) insert into random_test values (1, random()*100);
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explain (verbose on, costs off) insert into random_test values (random()*100, 1);
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drop table random_test;
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