-- -- FLOAT8 -- CREATE TABLE FLOAT8_TBL(f1 float8); INSERT INTO FLOAT8_TBL(f1) VALUES ('0.0'); INSERT INTO FLOAT8_TBL(f1) VALUES ('1004.30'); INSERT INTO FLOAT8_TBL(f1) VALUES ('-34.84'); INSERT INTO FLOAT8_TBL(f1) VALUES ('1.2345678901234e+200'); INSERT INTO FLOAT8_TBL(f1) VALUES ('1.2345678901234e-200'); SELECT '' AS five, FLOAT8_TBL.*; five | f1 ------+---------------------- | 0 | 1004.3 | -34.84 | 1.2345678901234e+200 | 1.2345678901234e-200 (5 rows) SELECT '' AS four, f.* FROM FLOAT8_TBL f WHERE f.f1 <> '1004.3'; four | f1 ------+---------------------- | 0 | -34.84 | 1.2345678901234e+200 | 1.2345678901234e-200 (4 rows) SELECT '' AS one, f.* FROM FLOAT8_TBL f WHERE f.f1 = '1004.3'; one | f1 -----+-------- | 1004.3 (1 row) SELECT '' AS three, f.* FROM FLOAT8_TBL f WHERE '1004.3' > f.f1; three | f1 -------+---------------------- | 0 | -34.84 | 1.2345678901234e-200 (3 rows) SELECT '' AS three, f.* FROM FLOAT8_TBL f WHERE f.f1 < '1004.3'; three | f1 -------+---------------------- | 0 | -34.84 | 1.2345678901234e-200 (3 rows) SELECT '' AS four, f.* FROM FLOAT8_TBL f WHERE '1004.3' >= f.f1; four | f1 ------+---------------------- | 0 | 1004.3 | -34.84 | 1.2345678901234e-200 (4 rows) SELECT '' AS four, f.* FROM FLOAT8_TBL f WHERE f.f1 <= '1004.3'; four | f1 ------+---------------------- | 0 | 1004.3 | -34.84 | 1.2345678901234e-200 (4 rows) SELECT '' AS three, f.f1, f.f1 * '-10' AS x FROM FLOAT8_TBL f WHERE f.f1 > '0.0'; three | f1 | x -------+----------------------+----------------------- | 1004.3 | -10043 | 1.2345678901234e+200 | -1.2345678901234e+201 | 1.2345678901234e-200 | -1.2345678901234e-199 (3 rows) SELECT '' AS three, f.f1, f.f1 + '-10' AS x FROM FLOAT8_TBL f WHERE f.f1 > '0.0'; three | f1 | x -------+----------------------+---------------------- | 1004.3 | 994.3 | 1.2345678901234e+200 | 1.2345678901234e+200 | 1.2345678901234e-200 | -10 (3 rows) SELECT '' AS three, f.f1, f.f1 / '-10' AS x FROM FLOAT8_TBL f WHERE f.f1 > '0.0'; three | f1 | x -------+----------------------+----------------------- | 1004.3 | -100.43 | 1.2345678901234e+200 | -1.2345678901234e+199 | 1.2345678901234e-200 | -1.2345678901234e-201 (3 rows) SELECT '' AS three, f.f1, f.f1 - '-10' AS x FROM FLOAT8_TBL f WHERE f.f1 > '0.0'; three | f1 | x -------+----------------------+---------------------- | 1004.3 | 1014.3 | 1.2345678901234e+200 | 1.2345678901234e+200 | 1.2345678901234e-200 | 10 (3 rows) SELECT '' AS one, f.f1 ^ '2.0' AS square_f1 FROM FLOAT8_TBL f where f.f1 = '1004.3'; one | square_f1 -----+------------ | 1008618.49 (1 row) -- absolute value SELECT '' AS five, f.f1, @f.f1 AS abs_f1 FROM FLOAT8_TBL f; five | f1 | abs_f1 ------+----------------------+---------------------- | 0 | 0 | 1004.3 | 1004.3 | -34.84 | 34.84 | 1.2345678901234e+200 | 1.2345678901234e+200 | 1.2345678901234e-200 | 1.2345678901234e-200 (5 rows) -- truncate SELECT '' AS five, f.f1, %f.f1 AS trunc_f1 FROM FLOAT8_TBL f; five | f1 | trunc_f1 ------+----------------------+---------------------- | 0 | 0 | 1004.3 | 1004 | -34.84 | -34 | 1.2345678901234e+200 | 1.2345678901234e+200 | 1.2345678901234e-200 | 0 (5 rows) -- round SELECT '' AS five, f.f1, f.f1 % AS round_f1 FROM FLOAT8_TBL f; five | f1 | round_f1 ------+----------------------+---------------------- | 0 | 0 | 1004.3 | 1004 | -34.84 | -35 | 1.2345678901234e+200 | 1.2345678901234e+200 | 1.2345678901234e-200 | 0 (5 rows) -- square root SELECT '' AS three, f.f1, |/f.f1 AS sqrt_f1 FROM FLOAT8_TBL f WHERE f.f1 > '0.0'; three | f1 | sqrt_f1 -------+----------------------+----------------------- | 1004.3 | 31.6906926399535 | 1.2345678901234e+200 | 1.11111110611109e+100 | 1.2345678901234e-200 | 1.11111110611109e-100 (3 rows) -- take exp of ln(f.f1) SELECT '' AS three, f.f1, : ( ; f.f1) AS exp_ln_f1 FROM FLOAT8_TBL f WHERE f.f1 > '0.0'; three | f1 | exp_ln_f1 -------+----------------------+----------------------- | 1004.3 | 1004.3 | 1.2345678901234e+200 | 1.23456789012338e+200 | 1.2345678901234e-200 | 1.23456789012339e-200 (3 rows) -- cube root SELECT '' AS five, f.f1, ||/f.f1 AS cbrt_f1 FROM FLOAT8_TBL f; five | f1 | cbrt_f1 ------+----------------------+---------------------- | 0 | 0 | 1004.3 | 10.014312837827 | -34.84 | -3.26607421344208 | 1.2345678901234e+200 | 4.97933859234765e+66 | 1.2345678901234e-200 | 2.3112042409018e-67 (5 rows) SELECT '' AS five, FLOAT8_TBL.*; five | f1 ------+---------------------- | 0 | 1004.3 | -34.84 | 1.2345678901234e+200 | 1.2345678901234e-200 (5 rows) UPDATE FLOAT8_TBL SET f1 = FLOAT8_TBL.f1 * '-1' WHERE FLOAT8_TBL.f1 > '0.0'; SELECT '' AS bad, f.f1 * '1e200' from FLOAT8_TBL f; ERROR: floating point exception! The last floating point operation either exceeded legal ranges or was a divide by zero SELECT '' AS bad, f.f1 ^ '1e200' from FLOAT8_TBL f; ERROR: pow() result is out of range SELECT '' AS bad, (; (f.f1)) from FLOAT8_TBL f where f.f1 = '0.0' ; ERROR: can't take log of zero SELECT '' AS bad, (; (f.f1)) from FLOAT8_TBL f where f.f1 < '0.0' ; ERROR: can't take log of a negative number SELECT '' AS bad, : (f.f1) from FLOAT8_TBL f; ERROR: exp() result is out of range SELECT '' AS bad, f.f1 / '0.0' from FLOAT8_TBL f; ERROR: float8div: divide by zero error SELECT '' AS five, FLOAT8_TBL.*; five | f1 ------+----------------------- | 0 | -34.84 | -1004.3 | -1.2345678901234e+200 | -1.2345678901234e-200 (5 rows) -- test for over and under flow INSERT INTO FLOAT8_TBL(f1) VALUES ('10e400'); ERROR: Input '10e400' is out of range for float8 INSERT INTO FLOAT8_TBL(f1) VALUES ('-10e400'); ERROR: Input '-10e400' is out of range for float8 INSERT INTO FLOAT8_TBL(f1) VALUES ('10e-400'); INSERT INTO FLOAT8_TBL(f1) VALUES ('-10e-400'); -- maintain external table consistency across platforms -- delete all values and reinsert well-behaved ones DELETE FROM FLOAT8_TBL; INSERT INTO FLOAT8_TBL(f1) VALUES ('0.0'); INSERT INTO FLOAT8_TBL(f1) VALUES ('-34.84'); INSERT INTO FLOAT8_TBL(f1) VALUES ('-1004.30'); INSERT INTO FLOAT8_TBL(f1) VALUES ('-1.2345678901234e+200'); INSERT INTO FLOAT8_TBL(f1) VALUES ('-1.2345678901234e-200'); SELECT '' AS five, FLOAT8_TBL.*; five | f1 ------+----------------------- | 0 | -34.84 | -1004.3 | -1.2345678901234e+200 | -1.2345678901234e-200 (5 rows)