PostgreSQL/Postgre SQL/Declare Variable — различия между версиями
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Admin (обсуждение | вклад) м (1 версия) |
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Текущая версия на 13:13, 26 мая 2010
Using variable declaration options
<source lang="sql">
postgres=# -- Using variable declaration options postgres=# postgres=# CREATE FUNCTION example_function () RETURNS text AS " postgres"# DECLARE postgres"# postgres"# -- Declare a constant integer with a default value of 5. postgres"# five CONSTANT INTEGER := 5; postgres"# postgres"# -- Declare an integer with a default value of 100 that cannot be NULL. postgres"# ten INTEGER NOT NULL := 10; postgres"# postgres"# -- Declare a character with a default value of "a". postgres"# letter CHAR DEFAULT ""a""; postgres"# postgres"# BEGIN postgres"# return letter; postgres"# END; postgres"# " LANGUAGE "plpgsql"; CREATE FUNCTION postgres=# postgres=# select example_function ();
example_function
a
(1 row) postgres=# postgres=# drop function example_function (); DROP FUNCTION postgres=# postgres=#
</source>
Variable Declarations
<source lang="sql">
postgres=# -- Variable Declarations postgres=# postgres=# CREATE FUNCTION identifier () RETURNS int4 AS " postgres"# DECLARE postgres"# postgres"# -- Declare an integer. postgres"# subject_id INTEGER; postgres"# postgres"# -- Declare a variable length character. postgres"# book_title VARCHAR(10); postgres"# postgres"# -- Declare a floating point number. postgres"# book_price FLOAT; postgres"# postgres"# BEGIN postgres"# return 10; postgres"# END; postgres"# " LANGUAGE "plpgsql"; ERROR: function "identifier" already exists with same argument types postgres=# postgres=# select identifier();
identifier
10
(1 row) postgres=# postgres=# drop function identifier(); DROP FUNCTION postgres=# postgres=#
</source>