在无法接受集合的上下文中调用的集合值函数

Question

我收到错误消息：

set-valued function called in context that cannot accept a set

在 RETURN QUERY EXECUTE 行执行此函数时：

PLSQL $ cat lookup_email.pl 
CREATE OR REPLACE FUNCTION app.lookup_email(ident_id bigint,sess bigint,company_id bigint,email varchar)
RETURNS SETOF RECORD as $$
DECLARE
    rec RECORD;
    comp_id bigint;
    server_session bigint;
    schema_name varchar;
    query varchar;
BEGIN
    schema_name:='comp' || company_id;
    select app.session.session into server_session from app.session where app.session.identity_id=ident_id and app.session.session=sess;
    IF FOUND
    THEN
        BEGIN
            query:='SELECT i.email,u.user_id FROM app.identity as i,' || schema_name || '.uzer as u WHERE i.email like ''%' || email || '%'' and i.identity_id=u.identity_id';
            RAISE NOTICE 'executing: %',query;
            RETURN QUERY EXECUTE query;
            RETURN;
        EXCEPTION
            WHEN OTHERS THEN
                RAISE NOTICE ' query error (%)',SQLERRM;

        END;
    END IF;
END;
$$ LANGUAGE plpgsql;

这是 psql 的输出：

dev=> select app.lookup_email(4,730035455897450,6,'u');
NOTICE:  executing: SELECT i.email,u.user_id FROM app.identity as i,comp6.uzer as u WHERE i.email like '%u%' and i.identity_id=u.identity_id
NOTICE:   query error (set-valued function called in context that cannot accept a set)
 lookup_email 
--------------
(0 rows)

我知道查询不包含任何错误，因为它在另一个 psql 会话中工作：

dev=> SELECT i.email,u.user_id FROM app.identity as i,comp6.uzer as u WHERE i.email like '%u%' and i.identity_id=u.identity_id;
     email      | user_id 
----------------+---------
 hola@mundo.com |       1
(1 row)

那么，如果我将我的函数声明为 RETURNS SETOF RECORD，为什么 Postgres 会抱怨？我的错误在哪里？

Answer 1

So, why is Postgres complaining if I declared my function being a SET of RECORD ??? Where is my error?

在 FROM 子句中调用您的 Set 返回函数。
始终指定您的类型。

它被称为集合返回函数，但您想指定复合类型

这完全正确，

RETURNS SETOF RECORD $$

但是，您可能需要调用它，

SELECT email, user_id
FROM 
    app.lookup_email(4,730035455897450,6,'u')
    AS t(email text, user_id integer)

不能在其中调用非类型化 SRF 的上下文是没有 table 定义的上下文。这种语法可能会变得令人讨厌，所以将 RETURNS SETOF RECORD 更改为

更容易

RETURNS TABLE(email text, user_id integer) AS $$

并使用没有列定义列表的函数

SELECT email, user_id
FROM app.lookup_email(4,730035455897450,6,'u')

在 the docs

中查找更多信息

Answer 2

在函数中定义输出列名喜欢下面

CREATE OR REPLACE FUNCTION app.lookup_email(ident_id bigint,sess bigint,company_id bigint,email varchar, OUT <column_name> <data type>, OUT ...)

在无法接受集合的上下文中调用的集合值函数

set-valued function called in context that cannot accept a set

postgresql

plpgsql

set-returning-functions