CREATE FUNCTION

柟誄

CREATE FUNCTION 垔幬婔婻桄䔇庘昄㔗CREATE OR REPLACE FUNCTION 儖襕幽录傺婔婻桄庘昄襕幽敪扵䯄橬䔇垔幬㔗

套悩寙劆庖婔婻昇嚟劉闼幽庘昄儌婘毺垔䔇昇嚟婺录傺㔗劥彍垄嚔婘嘷嬉昇嚟婺录傺㔗桄庘昄䔇劉庖婉脘启劯婔婻昇嚟婺䔇傂嘘婥橬劯湙埗昄䌂傋䔇庘昄劯劉㔗婉誺埗昄䌂傋婉劯䔇庘昄埇傖劯劉(認埆啔麉蘘)㔗

嘪䫘 CREATE OR REPLACE FUNCTION 敘桄婔婻䯄橬庘昄䔇垔幬㔗婉脘䫘認婻桹濘媞櫹婔婻庘昄䔇劉庖潡蔙埗昄䌂傋劥彍儌嚔录傺婔婻桄䔇庘昄㔗劯湙CREATE OR REPLACE FUNCTION 幘婉嚔噕螩嘹媞櫹婔婻䯄橬庘昄䔇誫啂䌂傋㔗襕啔認底庋愙嘹媙釂役鍴幽麉桄录傺庘昄㔗套悩嘪䫘 OUT 埗昄闼儌懟叿五鍴庖役鍴庘昄幋崡嘹婉脘媞櫹傂嘘 OUT 埗昄䔇䌂傋潡蔙劉庖㔗

套悩嘹役鍴䇽劯麉傺婔婻庘昄桄庘昄启斓庘昄儖滇婉劯䔇垂嘷嘹儌驔襕役鍴䯄橬嚘䫘庖蔕庘昄䔇蓇彍㔕蓖商㔕蓥埏単京京㔗嘪䫘 CREATE OR REPLACE FUNCTION 埇傖婘婉乘废嚘䫘臖庘昄䔇凹茇䔇嬉柊婋媞櫹庘昄垔幬㔗

录傺認婻庘昄䔇䫘潙儖潊婺庘昄䔇欔橬蔙㔗

埗昄

濘懟

臙埗黙誗33.3诙埡敘崔噿庯幥喍庘昄䔇媇敇㔗

噕螩嘹儖垯昘䔇 SQL 䌂傋臺濘䫘庯膷噖埗昄启誫啂唚㔗婉誺橬底䌂傋弄滯䔇䂖誗(懫套 numeric 䌂傋䔇來庥嘘)滇䫌婋北庘昄垂䯄蘘蘼䔇幽婫嚔赆 CREATE FUNCTION 变傴旇旇婄劂毬(幘儌滇婉喉赆臖彆潡嚺彽)㔗

PostgreSQL 噕螩庘昄麉蘘幘儌滇埻襕膷噖埗昄婉劯庹婻婉劯䔇庘昄埇傖劯劉㔗婉誺欔橬庘昄䔇 C 劉庖媙釂婉劯幘儌滇臘嘹媙釂䂍庽麉蘘䔇 C 庘昄婉劯䔇 C 劉庖(懫套嘪䫘埗昄䌂傋嘩婺 C 劉庖䔇婔鄘彖)㔗

套悩婴婻庘昄劯劉幽婫膷噖埗昄䌂傋幘䕩劯闼幽儌螴婺認婴婻庘昄滇婔湙䔇媘䘖欔橬 OUT 埗昄㔗啹溴婋麵䔇弄滯滇喾仕䔇

CREATE FUNCTION foo(int) ...
CREATE FUNCTION foo(int, out text) ...

套悩麉崉脄䫘 CREATE FUNCTION 幽婫鄘毺劏劯婔婻䕞湺桺傽闼幽臖桺傽埻媹蘘婔渇㔗襕麉桄媹蘘臖桺傽(埇脘滇婘嚔埏誺䘋婺)埇傖嘪䫘 LOAD 变傴㔗

嘪䫘 DROP FUNCTION 役鍴婔婻䫘潙垔幬庘昄㔗

锔婩嘪䫘䆯噄严䘯垔(埗黙 誗4.1.2.2)幥喍庘昄垔幬庖严婾蔯婉滇嘪䫘捞锔䔇剘嚘埙寙啘臺濘嚔敘桹冪㔗套悩婉嘪䫘䆯噄严䘯垔闼幽庘昄嘷麯麵䔇傂嘘剘嚘埙潡埉桩溹鄘媙釂䫘埯喍䔇桹濘锄锩㔗

襕脘垔幬庘昄䫘潙媙釂凹臖臺蘔橬 USAGE 溄鍊㔗

冋床

認麯滇婔底䞔剘䔇冋床䫘庯婞媷嘹嚔哋毯柇認婻变傴㔗敘崔媇敇启冋床埗黙誗33.3㔗

CREATE FUNCTION add(integer, integer) RETURNS integer
    AS 'select $1 + $2;'
    LANGUAGE SQL
    IMMUTABLE
    RETURNS NULL ON NULL INPUT;

彷䫘埗昄劉䫘 PL/pgSQL 躻嵂婔婻昘昄

CREATE OR REPLACE FUNCTION increment(i integer) RETURNS integer AS $$
        BEGIN
                RETURN i + 1;
        END;
$$ LANGUAGE plpgsql;

誫啂婔婻寙劆崔婻膷庺埗昄䔇螄嘘

CREATE FUNCTION dup(in int, out f1 int, out f2 text)
    AS $$ SELECT $1, CAST($1 AS text) || ' is text' $$
    LANGUAGE SQL;

SELECT * FROM dup(42);

嘹埇傖锔誺变劉滯䇞䔇崉劽䌂傋䔇螪濘喖阪婄幾劯湙䔇庋愙

CREATE TYPE dup_result AS (f1 int, f2 text);

CREATE FUNCTION dup(int) RETURNS dup_result
    AS $$ SELECT $1, CAST($1 AS text) || ' is text' $$
    LANGUAGE SQL;

SELECT * FROM dup(42);

噚垹攓

垄启 SQL:1999 麯䔇 CREATE FUNCTION 变傴䌂嚚嘖滇婉噚垹㔗匂攓启埇傖嘪䫘䔇臺蘔鄘滇婉埇䓂洉䔇㔗

婺庖启婔底噽垄䔇昄扞康係䂘噚垹argmode 埇傖婘 argname 幋嬉潡蔙幋劯喍嘖滇埻橬丸婔䓉螪濘滇湺庖噚垹䔇㔗

埽蓕