PostgreSQL 8.2.3 婺桺桺懼
劯锔	媆锔	䆹8. Data Types	媆誕	嬉誕

8.6. 婄儫䌂傋

PostgreSQL櫇毕 SQL 湺庖䔇 boolean 昄扞䌂傋㔗boolean 埻脘橬"true"(䩘)潡"false"(啺)婴婻䪽攕幋婔丸婬䓉"unknown"(橻䘖)䪽攕䫘 NULL 臘䴺㔗

"䩘"唚䔇橬昽桺橸唚滇

TRUE

't'

'true'

'y'

'yes'

'1'

凹庯"啺"嘹埇傖嘪䫘婋麵認底

FALSE

'f'

'false'

'n'

'no'

'0'

嘪䫘 TRUE 启 FALSE 認湙䔇庖䩚懫膄喘(幘滇 SQL 噚垹䔇䫘濘)㔗

冋8-2. 嘪䫘 boolean 䌂傋

CREATE TABLE test1 (a boolean, b text);
INSERT INTO test1 VALUES (TRUE, 'sic est');
INSERT INTO test1 VALUES (FALSE, 'non est');
SELECT * FROM test1;
 a |    b
---+---------
 t | sic est
 f | non est

SELECT * FROM test1 WHERE a;
 a |    b
---+---------
 t | sic est

冋8-2 滆䴺庖嘪䫘庖應 t 启 f 膷庺 boolean 昄唚䔇冋床㔗

boolean 嘪䫘 1 庖誗庻嗘䷺閘㔗

劯锔	饡釕	嬉誕
斖橘/施閘䌂傋	婪婔亓	庹嘘䌂傋