PL/pgSQL的 RETURN NEXT例子

时间 2019-11-17

标签 pgsql return 例子繁體版

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从网上找到例子：sql

能够说，RETURN NEXT要用在循环中:函数

例子一：spa

数据准备：code

CREATE TABLE foo (fooid INT, foosubid INT, fooname TEXT);
INSERT INTO foo VALUES (1, 2, 'three');
INSERT INTO foo VALUES (4, 5, 'six');

生成函数：blog

CREATE OR REPLACE FUNCTION getAllFoo() RETURNS SETOF foo AS
$BODY$
DECLARE
    r foo%rowtype;
BEGIN
    FOR r IN SELECT * FROM foo
    WHERE fooid > 0
    LOOP
        -- can do some processing here
        RETURN NEXT r; -- return next row of SELECT
    END LOOP;
    RETURN;
END
$BODY$
LANGUAGE 'plpgsql';

运行结果：three

pgsql=# SELECT * FROM getallfoo();
 fooid | foosubid | fooname 
-------+----------+---------
     1 |        2 | three
     4 |        5 | six
(2 rows)

pgsql=#

例子二：get

数据准备：class

CREATE TABLE test (textcol varchar(10), intcol int); 
INSERT INTO test VALUES ('a', 1); 
INSERT INTO test VALUES ('a', 2); 
INSERT INTO test VALUES ('b', 5); 
INSERT INTO test VALUES ('b', 6);

生成函数：test

CREATE OR REPLACE FUNCTION ReturnNexting(pText Text) RETURNS SETOF test AS $$ 
        DECLARE 
                rec RECORD; 
        BEGIN 
                FOR rec IN SELECT * FROM test WHERE textcol = pText LOOP 
                        RETURN NEXT rec; 
                END LOOP; 
                RETURN; 
        END; 
$$ 
LANGUAGE plpgsql;

运行结果：循环

pgsql=# SELECT * FROM ReturnNexting('a');
 textcol | intcol 
---------+--------
 a       |      1
 a       |      2
(2 rows)

pgsql=#