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PostgreSQL/Data Type/Boolean - История изменений
2026-05-24T22:39:15Z
История изменений этой страницы в вики
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http://www.sqle.ru/index.php?title=PostgreSQL/Data_Type/Boolean&diff=4742&oldid=prev
в 13:45, 26 мая 2010
2010-05-26T13:45:56Z
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<td colspan="1" style="background-color: white; color:black; text-align: center;">← Предыдущая</td>
<td colspan="1" style="background-color: white; color:black; text-align: center;">Версия 13:45, 26 мая 2010</td>
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http://www.sqle.ru/index.php?title=PostgreSQL/Data_Type/Boolean&diff=4743&oldid=prev
Admin: 1 версия
2010-05-26T10:14:14Z
<p>1 версия</p>
<p><b>Новая страница</b></p><div>==boolean value "t"==<br />
<br />
<br />
<br />
<br />
<!-- start source code --><br />
<br />
<source lang="sql"><br />
<br />
postgres=#<br />
postgres=#<br />
postgres=# CREATE TABLE myTable (isbn text, in_stock boolean);<br />
CREATE TABLE<br />
postgres=#<br />
postgres=# INSERT INTO myTable VALUES ("0385121679", true);<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("039480001X", "t");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("044100590X", "true");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0451198492", false);<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0394900014", "0");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0441172717", "1");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0451160916");<br />
INSERT 0 1<br />
postgres=#<br />
postgres=# select * from myTable;<br />
isbn | in_stock<br />
------------+----------<br />
0385121679 | t<br />
039480001X | t<br />
044100590X | t<br />
0451198492 | f<br />
0394900014 | f<br />
0441172717 | t<br />
0451160916 |<br />
(7 rows)<br />
postgres=#<br />
postgres=# SELECT * FROM myTable WHERE in_stock != "t";<br />
isbn | in_stock<br />
------------+----------<br />
0451198492 | f<br />
0394900014 | f<br />
(2 rows)<br />
postgres=#<br />
postgres=# drop table myTable;<br />
DROP TABLE<br />
postgres=#<br />
<br />
</source><br />
<br />
<br />
<br />
<br />
==Checking Boolean values: yes==<br />
<br />
<br />
<br />
<br />
<!-- start source code --><br />
<br />
<source lang="sql"><br />
<br />
postgres=#<br />
postgres=# CREATE TABLE myTable (isbn text, in_stock boolean);<br />
CREATE TABLE<br />
postgres=#<br />
postgres=# INSERT INTO myTable VALUES ("0385121679", true);<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("039480001X", "t");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("044100590X", "true");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0451198492", false);<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0394900014", "0");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0441172717", "1");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0451160916");<br />
INSERT 0 1<br />
postgres=#<br />
postgres=# -- Checking Boolean values<br />
postgres=#<br />
postgres=# SELECT * FROM myTable WHERE in_stock = "yes";<br />
isbn | in_stock<br />
------------+----------<br />
0385121679 | t<br />
039480001X | t<br />
044100590X | t<br />
0441172717 | t<br />
(4 rows)<br />
postgres=#<br />
postgres=#<br />
postgres=# drop table myTable;<br />
DROP TABLE<br />
postgres=#<br />
postgres=#<br />
<br />
</source><br />
<br />
<br />
<br />
<br />
==Checking for "false" Boolean values==<br />
<br />
<br />
<br />
<br />
<!-- start source code --><br />
<br />
<source lang="sql"><br />
<br />
postgres=#<br />
postgres=#<br />
postgres=# CREATE TABLE myTable (isbn text, in_stock boolean);<br />
CREATE TABLE<br />
postgres=#<br />
postgres=# INSERT INTO myTable VALUES ("0385121679", true);<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("039480001X", "t");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("044100590X", "true");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0451198492", false);<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0394900014", "0");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0441172717", "1");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0451160916");<br />
INSERT 0 1<br />
postgres=#<br />
postgres=# select * from myTable;<br />
isbn | in_stock<br />
------------+----------<br />
0385121679 | t<br />
039480001X | t<br />
044100590X | t<br />
0451198492 | f<br />
0394900014 | f<br />
0441172717 | t<br />
0451160916 |<br />
(7 rows)<br />
postgres=#<br />
postgres=# -- Checking for "false" Boolean values<br />
postgres=#<br />
postgres=# SELECT * FROM myTable WHERE in_stock = "no";<br />
isbn | in_stock<br />
------------+----------<br />
0451198492 | f<br />
0394900014 | f<br />
(2 rows)<br />
postgres=#<br />
postgres=#<br />
postgres=#<br />
postgres=# drop table myTable;<br />
DROP TABLE<br />
postgres=#<br />
postgres=#<br />
<br />
</source><br />
<br />
<br />
<br />
<br />
==Compare the value of a boolean field against any of the values==<br />
<br />
<br />
<br />
<br />
<!-- start source code --><br />
<br />
<source lang="sql"><br />
<br />
postgres=#<br />
postgres=#<br />
postgres=# CREATE TABLE myTable (isbn text, in_stock boolean);<br />
CREATE TABLE<br />
postgres=#<br />
postgres=# INSERT INTO myTable VALUES ("0385121679", true);<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("039480001X", "t");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("044100590X", "true");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0451198492", false);<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0394900014", "0");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0441172717", "1");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0451160916");<br />
INSERT 0 1<br />
postgres=#<br />
postgres=# select * from myTable;<br />
isbn | in_stock<br />
------------+----------<br />
0385121679 | t<br />
039480001X | t<br />
044100590X | t<br />
0451198492 | f<br />
0394900014 | f<br />
0441172717 | t<br />
0451160916 |<br />
(7 rows)<br />
postgres=#<br />
postgres=# -- Compare the value of a boolean field against any of the values<br />
postgres=#<br />
postgres=# SELECT * FROM myTable WHERE NOT in_stock;<br />
isbn | in_stock<br />
------------+----------<br />
0451198492 | f<br />
0394900014 | f<br />
(2 rows)<br />
postgres=#<br />
postgres=# drop table myTable;<br />
DROP TABLE<br />
postgres=#<br />
<br />
</source><br />
<br />
<br />
<br />
<br />
==Implying Boolean "true"==<br />
<br />
<br />
<br />
<br />
<!-- start source code --><br />
<br />
<source lang="sql"><br />
<br />
postgres=#<br />
postgres=# CREATE TABLE myTable (isbn text, in_stock boolean);<br />
CREATE TABLE<br />
postgres=#<br />
postgres=# INSERT INTO myTable VALUES ("0385121679", true);<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("039480001X", "t");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("044100590X", "true");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0451198492", false);<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0394900014", "0");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0441172717", "1");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0451160916");<br />
INSERT 0 1<br />
postgres=#<br />
postgres=# -- Implying Boolean "true"<br />
postgres=#<br />
postgres=# SELECT * FROM myTable WHERE in_stock;<br />
isbn | in_stock<br />
------------+----------<br />
0385121679 | t<br />
039480001X | t<br />
044100590X | t<br />
0441172717 | t<br />
(4 rows)<br />
postgres=#<br />
postgres=# drop table myTable;<br />
DROP TABLE<br />
postgres=#<br />
<br />
</source><br />
<br />
<br />
<br />
<br />
==NOT for boolean value==<br />
<br />
<br />
<br />
<br />
<!-- start source code --><br />
<br />
<source lang="sql"><br />
postgres=#<br />
postgres=#<br />
postgres=# CREATE TABLE myTable (isbn text, in_stock boolean);<br />
CREATE TABLE<br />
postgres=#<br />
postgres=# INSERT INTO myTable VALUES ("0385121679", true);<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("039480001X", "t");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("044100590X", "true");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0451198492", false);<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0394900014", "0");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0441172717", "1");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0451160916");<br />
INSERT 0 1<br />
postgres=#<br />
postgres=# select * from myTable;<br />
isbn | in_stock<br />
------------+----------<br />
0385121679 | t<br />
039480001X | t<br />
044100590X | t<br />
0451198492 | f<br />
0394900014 | f<br />
0441172717 | t<br />
0451160916 |<br />
(7 rows)<br />
postgres=#<br />
postgres=#<br />
postgres=# SELECT * FROM myTable WHERE NOT in_stock;<br />
isbn | in_stock<br />
------------+----------<br />
0451198492 | f<br />
0394900014 | f<br />
(2 rows)<br />
postgres=#<br />
postgres=#<br />
postgres=#<br />
postgres=# drop table myTable;<br />
DROP TABLE<br />
<br />
</source><br />
<br />
<br />
<br />
<br />
==NULL will not register as either true or false==<br />
<br />
<br />
<br />
<br />
<!-- start source code --><br />
<br />
<source lang="sql"><br />
<br />
postgres=#<br />
postgres=#<br />
postgres=# CREATE TABLE myTable (isbn text, in_stock boolean);<br />
CREATE TABLE<br />
postgres=#<br />
postgres=# INSERT INTO myTable VALUES ("0385121679", true);<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("039480001X", "t");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("044100590X", "true");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0451198492", false);<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0394900014", "0");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0441172717", "1");<br />
INSERT 0 1<br />
postgres=# INSERT INTO myTable VALUES ("0451160916");<br />
INSERT 0 1<br />
postgres=#<br />
postgres=# select * from myTable;<br />
isbn | in_stock<br />
------------+----------<br />
0385121679 | t<br />
039480001X | t<br />
044100590X | t<br />
0451198492 | f<br />
0394900014 | f<br />
0441172717 | t<br />
0451160916 |<br />
(7 rows)<br />
postgres=#<br />
postgres=# -- NULL will not register as either true or false<br />
postgres=#<br />
postgres=# SELECT * FROM myTable WHERE in_stock IS NULL;<br />
isbn | in_stock<br />
------------+----------<br />
0451160916 |<br />
(1 row)<br />
postgres=#<br />
postgres=#<br />
postgres=# drop table myTable;<br />
DROP TABLE<br />
postgres=#<br />
<br />
</source><br />
<br />
<br />
<br />
<br />
==The difference between true and "true"==<br />
<br />
<br />
<br />
<br />
<!-- start source code --><br />
<br />
<source lang="sql"><br />
postgres=#<br />
postgres=# -- The difference between true and "true"<br />
postgres=#<br />
postgres=# SELECT true AS boolean_t,<br />
postgres-# "true" AS string_t,<br />
postgres-# false AS boolean_f,<br />
postgres-# "false" AS string_f;<br />
boolean_t | string_t | boolean_f | string_f<br />
-----------+----------+-----------+----------<br />
t | true | f | false<br />
(1 row)<br />
postgres=#<br />
<br />
</source><br />
<br />
<br />
<br />
<br />
==Using the boolean type==<br />
<br />
<br />
<br />
<br />
<!-- start source code --><br />
<br />
<source lang="sql"><br />
<br />
postgres=#<br />
postgres=#<br />
postgres=# -- Using the boolean type<br />
postgres=#<br />
postgres=# CREATE TABLE test1 (a boolean, b text);<br />
CREATE TABLE<br />
postgres=# INSERT INTO test1 VALUES (TRUE, "sic est");<br />
INSERT 0 1<br />
postgres=# INSERT INTO test1 VALUES (FALSE, "non est");<br />
INSERT 0 1<br />
postgres=#<br />
postgres=# SELECT * FROM test1;<br />
a | b<br />
---+---------<br />
t | sic est<br />
f | non est<br />
(2 rows)<br />
postgres=#<br />
postgres=# SELECT * FROM test1 WHERE a;<br />
a | b<br />
---+---------<br />
t | sic est<br />
(1 row)<br />
postgres=#<br />
postgres=# drop table test1;<br />
DROP TABLE<br />
postgres=#<br />
<br />
</source></div>
Admin