select_having.sql

关系型数据库 Postgresql 6.5.2

--
-- select_having.sql
--

-- load test data
CREATE TABLE test_having (a int, b int, c char(8), d char);
INSERT INTO test_having VALUES (0, 1, 'XXXX', 'A');
INSERT INTO test_having VALUES (1, 2, 'AAAA', 'b');
INSERT INTO test_having VALUES (2, 2, 'AAAA', 'c');
INSERT INTO test_having VALUES (3, 3, 'BBBB', 'D');
INSERT INTO test_having VALUES (4, 3, 'BBBB', 'e');
INSERT INTO test_having VALUES (5, 3, 'bbbb', 'F');
INSERT INTO test_having VALUES (6, 4, 'cccc', 'g');
INSERT INTO test_having VALUES (7, 4, 'cccc', 'h');
INSERT INTO test_having VALUES (8, 4, 'CCCC', 'I');
INSERT INTO test_having VALUES (9, 4, 'CCCC', 'j');

SELECT b, c FROM test_having
	GROUP BY b, c HAVING count(*) = 1;

SELECT lower(c), count(c) FROM test_having
	GROUP BY lower(c) HAVING count(*) > 2 OR min(a) = max(a);

SELECT c, max(a) FROM test_having
	GROUP BY c HAVING count(*) > 2 OR min(a) = max(a);

DROP TABLE test_having;