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PostgreSQL/Select Query/Row - История изменений
2026-04-05T21:35:44Z
История изменений этой страницы в вики
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http://sqle.ru/index.php?title=PostgreSQL/Select_Query/Row&diff=4890&oldid=prev
в 13:45, 26 мая 2010
2010-05-26T13:45:56Z
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http://sqle.ru/index.php?title=PostgreSQL/Select_Query/Row&diff=4891&oldid=prev
Admin: 1 версия
2010-05-26T10:14:25Z
<p>1 версия</p>
<p><b>Новая страница</b></p><div>==Cast row function==<br />
<br />
<br />
<br />
<br />
<!-- start source code --><br />
<br />
<source lang="sql"><br />
<br />
postgres=#<br />
postgres=# CREATE FUNCTION getf1(mytable) RETURNS int<br />
postgres-# AS "SELECT $1.f1"<br />
postgres-# LANGUAGE SQL;<br />
CREATE FUNCTION<br />
postgres=#<br />
postgres=# CREATE TYPE myrowtype AS (f1 int, f2 text, f3 numeric);<br />
CREATE TYPE<br />
postgres=#<br />
postgres=# CREATE FUNCTION getf1(myrowtype) RETURNS int<br />
postgres-# AS "SELECT $1.f1"<br />
postgres-# LANGUAGE SQL;<br />
CREATE FUNCTION<br />
postgres=#<br />
postgres=# SELECT getf1(ROW(1,2.5,"this is a test")::mytable);<br />
getf1<br />
-------<br />
1<br />
(1 row)<br />
postgres=#<br />
postgres=# SELECT getf1(CAST(ROW(11,"this is a test",2.5) AS myrowtype));<br />
getf1<br />
-------<br />
11<br />
(1 row)<br />
postgres=#<br />
postgres=# drop function getf1(myrowtype);<br />
DROP FUNCTION<br />
postgres=# drop type myrowtype;<br />
DROP TYPE<br />
postgres=# drop table mytable cascade;<br />
NOTICE: drop cascades to function getf1(mytable)<br />
DROP TABLE<br />
postgres=#<br />
postgres=#<br />
<br />
</source><br />
<br />
<br />
<br />
<br />
==Pass "row" function to function==<br />
<br />
<br />
<br />
<br />
<!-- start source code --><br />
<br />
<source lang="sql"><br />
<br />
postgres=#<br />
postgres=#<br />
postgres=# CREATE TABLE mytable(f1 int, f2 float, f3 text);<br />
CREATE TABLE<br />
postgres=#<br />
postgres=# CREATE FUNCTION getf1(mytable) RETURNS int AS "SELECT $1.f1" LANGUAGE SQL;<br />
CREATE FUNCTION<br />
postgres=#<br />
postgres=# -- No cast needed since only one getf1() exists<br />
postgres=# SELECT getf1(ROW(1,2.5,"this is a test"));<br />
getf1<br />
-------<br />
1<br />
(1 row)<br />
postgres=#<br />
postgres=#<br />
postgres=# drop function getf1(mytable);<br />
DROP FUNCTION<br />
postgres=# drop table mytable;<br />
DROP TABLE<br />
postgres=#<br />
postgres=#<br />
postgres=#<br />
<br />
</source><br />
<br />
<br />
<br />
<br />
==Row Constructors==<br />
<br />
<br />
<br />
<br />
<!-- start source code --><br />
<br />
<source lang="sql"><br />
<br />
postgres=# -- Row Constructors<br />
postgres=#<br />
postgres=# SELECT ROW(1,2.5,"this is a test");<br />
row<br />
--------------------------<br />
(1,2.5,"this is a test")<br />
(1 row)<br />
postgres=#<br />
postgres=#<br />
<br />
</source><br />
<br />
<br />
<br />
<br />
==Using "Row" function in a function==<br />
<br />
<br />
<br />
<br />
<!-- start source code --><br />
<br />
<source lang="sql"><br />
postgres=#<br />
postgres=# CREATE TABLE emp (<br />
postgres(# name text,<br />
postgres(# salary numeric,<br />
postgres(# age integer,<br />
postgres(# cubicle point<br />
postgres(# );<br />
CREATE TABLE<br />
postgres=#<br />
postgres=# insert into emp values ("None", 1000.0, 25, "(2,2)");<br />
INSERT 0 1<br />
postgres=#<br />
postgres=#<br />
postgres=# CREATE FUNCTION new_emp() RETURNS emp AS $$<br />
postgres$# SELECT ROW("None", 1000.0, 25, "(2,2)")::emp;<br />
postgres$# $$ LANGUAGE SQL;<br />
CREATE FUNCTION<br />
postgres=#<br />
postgres=# SELECT (new_emp()).name;<br />
REATE<br />
name<br />
------<br />
None<br />
(1 row)<br />
postgres=#<br />
postgres=# drop function new_emp();<br />
DROP FUNCTION<br />
postgres=# drop table emp;<br />
DROP TABLE<br />
postgres=#<br />
postgres=#<br />
<br />
</source></div>
Admin