PL/pgSQL的 RETURN NEXT例子

从网上找到例子：

可以说，RETURN NEXT要用在循环中:

例子一：

数据准备：

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：

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：

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

pgsql=# 

例子二：

数据准备：

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：

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：

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

pgsql=#