从带有 OUT 参数的函数返回 [英] Returning from a function with OUT parameter

问题描述

我有一个错误，但我不知道问题出在哪里.

我想执行一个函数并从由列默认填充的列返回一个值，一个序列 - 相当于 currval(sequence).

我使用:
PostgreSQL 9.0
pgAdmin III

CREATE OR REPLACE FUNCTION name_function(在 param_1 字符中变化, 出 param_2 bigint)作为$$开始INSERT INTO 表 (collumn_seq,param_1) VALUES (DEFAULT,param_1)返回 collumn_seq；--where:collumn_seq 引用一个列序列..结尾;$$语言 plpgsql 易失性；

我可以创建没有错误的函数，但是在尝试执行时，返回以下错误:

<块引用>

SELECT name_function('GHGHGH');错误:查询没有结果数据的目标

解决方案

它会像这样工作:

CREATE OR REPLACE FUNCTION name_function(param_1 varchar, OUT param_2 bigint)语言 plpgsql AS$func$开始INSERT INTO table (collumn_seq, param_1) -- param_1"也是列名?值(默认，param_1)返回 collumn_seq进入参数2；结尾$func$;

通常，您会添加一个 RETURN 语句，但是对于 OUT 参数，这是可选的.
请参阅手册了解更多详情:

• 从函数返回
• 使用单个执行查询行结果

简单的情况可以用一个普通的 SQL 函数来覆盖.
您可以省略应获得其 DEFAULT 值的目标列.
在这种情况下，您也可以使用 RETURNS 子句:

CREATE OR REPLACE FUNCTION name_function(param_1 varchar)返回 bigint语言 sql AS$func$INSERT INTO table (param_1) -- "param_1";还有列名?值(参数 1)返回 collumn_seq;$func$;

I have an error, but I don't know what the problem is.

I want execute a function and return a value from a column filled in by the column default, a sequence - the equivalent of currval(sequence).

I use:
PostgreSQL 9.0
pgAdmin III

CREATE OR REPLACE FUNCTION name_function(in param_1 character varying
                                      , out param_2 bigint)
  AS
$$
BEGIN
    INSERT INTO table (collumn_seq,param_1) VALUES (DEFAULT,param_1)
    returning collumn_seq;
--where:collumn_seq reference a collumn serial..
END;
$$
  LANGUAGE plpgsql VOLATILE;

I can create the function without error but when trying to execute, the following error is returned:

SELECT name_function('GHGHGH');

ERROR: The query has no destination for result data

解决方案

It would work like this:

CREATE OR REPLACE FUNCTION name_function(param_1 varchar
                                   , OUT param_2 bigint)
  LANGUAGE plpgsql AS
$func$
BEGIN
    INSERT INTO table (collumn_seq, param_1)  -- "param_1" also the column name?
    VALUES (DEFAULT, param_1)
    RETURNING collumn_seq
    INTO param2;
END
$func$;

Normally, you would add a RETURN statement, but with OUT parameters, this is optional.
Refer to the manual for more details:

• Returning from a function
• Executing a Query with a Single-row Result

The simple case can be covered with a plain SQL function.
And you can omit the target column that shall get its DEFAULT value.
And you can just as well use a RETURNS clause in this case:

CREATE OR REPLACE FUNCTION name_function(param_1 varchar)
  RETURNS bigint
  LANGUAGE sql AS
$func$
INSERT INTO table (param_1)  -- "param_1" also the column name?
VALUES (param_1)
RETURNING collumn_seq;
$func$;

这篇关于从带有 OUT 参数的函数返回的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！