1-- 2-- SELECT_HAVING 3-- 4 5-- load test data 6CREATE TABLE test_having (a int, b int, c char(8), d char); 7INSERT INTO test_having VALUES (0, 1, 'XXXX', 'A'); 8INSERT INTO test_having VALUES (1, 2, 'AAAA', 'b'); 9INSERT INTO test_having VALUES (2, 2, 'AAAA', 'c'); 10INSERT INTO test_having VALUES (3, 3, 'BBBB', 'D'); 11INSERT INTO test_having VALUES (4, 3, 'BBBB', 'e'); 12INSERT INTO test_having VALUES (5, 3, 'bbbb', 'F'); 13INSERT INTO test_having VALUES (6, 4, 'cccc', 'g'); 14INSERT INTO test_having VALUES (7, 4, 'cccc', 'h'); 15INSERT INTO test_having VALUES (8, 4, 'CCCC', 'I'); 16INSERT INTO test_having VALUES (9, 4, 'CCCC', 'j'); 17 18SELECT b, c FROM test_having 19 GROUP BY b, c HAVING count(*) = 1 ORDER BY b, c; 20 21-- HAVING is effectively equivalent to WHERE in this case 22SELECT b, c FROM test_having 23 GROUP BY b, c HAVING b = 3 ORDER BY b, c; 24 25SELECT lower(c), count(c) FROM test_having 26 GROUP BY lower(c) HAVING count(*) > 2 OR min(a) = max(a) 27 ORDER BY lower(c); 28 29SELECT c, max(a) FROM test_having 30 GROUP BY c HAVING count(*) > 2 OR min(a) = max(a) 31 ORDER BY c; 32 33-- test degenerate cases involving HAVING without GROUP BY 34-- Per SQL spec, these should generate 0 or 1 row, even without aggregates 35 36SELECT min(a), max(a) FROM test_having HAVING min(a) = max(a); 37SELECT min(a), max(a) FROM test_having HAVING min(a) < max(a); 38 39-- errors: ungrouped column references 40SELECT a FROM test_having HAVING min(a) < max(a); 41SELECT 1 AS one FROM test_having HAVING a > 1; 42 43-- the really degenerate case: need not scan table at all 44SELECT 1 AS one FROM test_having HAVING 1 > 2; 45SELECT 1 AS one FROM test_having HAVING 1 < 2; 46 47-- and just to prove that we aren't scanning the table: 48SELECT 1 AS one FROM test_having WHERE 1/a = 1 HAVING 1 < 2; 49 50DROP TABLE test_having; 51