CTE 按预期工作，但在包装到函数中时不工作

Question

CTE 按预期工作，但在包装到函数中时不工作

Gob*_*0st 7 postgresql stored-procedures cte plpgsql

--testing table
CREATE TABLE public.test_patient_table (
                entity_id INTEGER NOT NULL,
                site_held_at INTEGER NOT NULL,
                CONSTRAINT entityid_pk PRIMARY KEY (entity_id)
);

CREATE TABLE public.test_messageq_table (
                entity_id VARCHAR NOT NULL,
                master_id INTEGER NOT NULL,
                message_body VARCHAR NOT NULL,
                CONSTRAINT mq_entity_id_pk PRIMARY KEY (entity_id)
);

CREATE INDEX test_patient_table_siteid_idx
 ON public.test_patient_table
 ( site_held_at );

ALTER TABLE public.test_messageq_table
ADD CONSTRAINT test_patient_table_test_messageq_table_fk
FOREIGN KEY (master_id)
REFERENCES public.test_patient_table (entity_id)
ON DELETE NO ACTION
ON UPDATE NO ACTION
NOT DEFERRABLE;

--test patient data
insert into test_patient_table values (1, 11111);
insert into test_patient_table values (2, 11111);
insert into test_patient_table values (3, 11111);
insert into test_patient_table values (4, 11111);

insert into test_patient_table values (5, 22222);
insert into test_patient_table values (6, 22222);
insert into test_patient_table values (7, 22222);
insert into test_patient_table values (8, 22222);

insert into test_patient_table values (9, 33333);
insert into test_patient_table values (10, 33333);

insert into test_patient_table values (11, 44444);

--testing message
insert into test_messageq_table values (1, 1, 'aaa');
insert into test_messageq_table values (2, 1, 'aaa');
insert into test_messageq_table values (3, 1, 'aaa');
insert into test_messageq_table values (4, 1, 'aaa');
insert into test_messageq_table values (5, 2, 'aaa');
insert into test_messageq_table values (6, 2, 'aaa');
insert into test_messageq_table values (7, 5, 'aaa');
insert into test_messageq_table values (8, 8, 'aaa');
insert into test_messageq_table values (9, 11, 'aaa');
insert into test_messageq_table values (10, 11, 'bbb');

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当我试图从我感兴趣的站点的消息表中查找所有消息时，我写了一个 CTE 并且它工作正常，假设我对站点 11111 和 22222 感兴趣：

WITH patient_msg_in_branches AS (
    select distinct test_messageq_table.master_id AS patient_id,
    test_patient_table.site_held_at as site_id
    from test_messageq_table 
    inner join test_patient_table 
    ON test_messageq_table.master_id = test_patient_table.entity_id 
    and site_held_at in (11111,22222) order by patient_id
),
messages_for_patients AS(
    select * from test_messageq_table where master_id in 
        (select patient_msg_in_branches.patient_id 
            from patient_msg_in_branches)
)select * from messages_for_patients

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结果如预期：

"1";1;"aaa"
"2";1;"aaa"
"3";1;"aaa"
"4";1;"aaa"
"5";2;"aaa"
"6";2;"aaa"
"7";5;"aaa"
"8";8;"aaa"

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但是当我将整个事情包装在一个函数中时，它返回了错误的行。你能帮我看看为什么吗？

drop function getMessageFromSites(text);
CREATE OR REPLACE FUNCTION getMessageFromSites(IN ids TEXT) RETURNS 
setof test_messageq_table AS $$ 
DECLARE
       sites INT[];
       result test_messageq_table%rowtype;

BEGIN
       sites = string_to_array(ids,',');
        raise info 'entire array: %', sites;

WITH patient_msg_in_branches AS (
    select distinct test_messageq_table.master_id AS patient_id,
    test_patient_table.site_held_at as site_id
    from test_messageq_table 
    inner join test_patient_table 
    ON test_messageq_table.master_id = test_patient_table.entity_id 
    and site_held_at = ANY(sites) order by patient_id
),
messages_for_patients AS(
    select * from test_messageq_table where master_id in 
        (select patient_msg_in_branches.patient_id 
            from patient_msg_in_branches)
)select * into result from messages_for_patients;
return query select * from result;
END;     
$$ LANGUAGE plpgsql;

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使用该功能时：

select * from getMessageFromSites('11111,22222');
select * from getMessageFromSites('1')
select * from getMessageFromSites('33333')

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它总是在多行下方返回相同的结果，但显然是错误的行，为什么？你能帮忙吗？

"1";1;"aaa"
"2";1;"aaa"
"3";1;"aaa"
"4";1;"aaa"
"5";2;"aaa"
"6";2;"aaa"
"9";11;"aaa"
"10";11;"bbb"

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解决方案

感谢@a_horse_with_no_name，现在我有两种可行的解决方案，一种使用 sql，一种使用 pl/pgsql：

解决方案 1 (pl/pgsql)

CREATE OR REPLACE FUNCTION getMessageFromSites(IN ids TEXT) RETURNS 
setof test_messageq_table AS $$ 
DECLARE
       sites INT[];
       result test_messageq_table%rowtype;

BEGIN
       sites = string_to_array(ids,',');
       raise info 'entire array: %', sites;
 return QUERY

    WITH patient_msg_in_branches AS (
        select distinct test_messageq_table.master_id AS patient_id,
        test_patient_table.site_held_at as site_id
        from test_messageq_table 
        inner join test_patient_table 
        ON test_messageq_table.master_id = test_patient_table.entity_id 
        and site_held_at = ANY(sites) order by patient_id
    ),
    messages_for_patients AS(
        select * from test_messageq_table where master_id in 
            (select patient_msg_in_branches.patient_id 
                from patient_msg_in_branches)
    )
    select * from messages_for_patients;

END;     
$$ LANGUAGE plpgsql;

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解决方案2（sql）

CREATE OR REPLACE FUNCTION getMessageFromSites2(ids TEXT) RETURNS 
   setof test_messageq_table 
AS 
$$ 
  WITH patient_msg_in_branches AS (
      select distinct test_messageq_table.master_id AS patient_id,
             test_patient_table.site_held_at as site_id
      from test_messageq_table 
      join test_patient_table ON test_messageq_table.master_id = test_patient_table.entity_id 
                                and site_held_at = ANY (string_to_array($1,',')::int[]) 
  ),
  messages_for_patients AS
  (
    select * 
    from test_messageq_table 
    where master_id in (select patient_msg_in_branches.patient_id 
                        from patient_msg_in_branches)
  )
  select * 
  from messages_for_patients;
$$ 
LANGUAGE sql;

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代码测试

select * from getMessageFromSites('11111,44444');
select * from getMessageFromSites('22222');
select * from getMessageFromSites('1')
select * from getMessageFromSites('33333')

select * from getMessageFromSites2('11111');
select * from getMessageFromSites2('22222');
select * from getMessageFromSites2('33333');
select * from getMessageFromSites('44444,11111');
select * from getMessageFromSites('1');

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两个 PG 存储过程都按预期工作！

解决方案 3：一个更好的简化解决方案，请参见下面 Erwin 的回答。

现已结案！

Answer 1

a_h*_*ame 8

我认为这是因为您只从查询结果中返回第一行。

该select ... into ...会只检索一行和query select * from result只返回单个记录：

您也不需要 PL/pgSQL 函数，一个普通的 SQL 函数就可以正常工作：

CREATE OR REPLACE FUNCTION getMessageFromSites(ids TEXT) RETURNS 
   setof test_messageq_table 
AS 
$$ 
  WITH patient_msg_in_branches AS (
      select distinct test_messageq_table.master_id AS patient_id,
             test_patient_table.site_held_at as site_id
      from test_messageq_table 
         join test_patient_table ON test_messageq_table.master_id = test_patient_table.entity_id 
                                and site_held_at = ANY (string_to_array(ids,',')::int[]) 
  ),
  messages_for_patients AS
  (
    select * 
    from test_messageq_table 
    where master_id in (select patient_msg_in_branches.patient_id 
                        from patient_msg_in_branches)
  )
  select * 
  from messages_for_patients;
$$ 
LANGUAGE sql;

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请注意，CTE 内部的 order by 并不是很有用。您必须对最终选择进行排序，而不是对中间步骤进行排序。

如果你确实需要 PL/pgSQL 因为你在函数中做了更多的事情，你应该简单地将它更改为：

begin
  ....
  return query
    WITH patient_msg_in_branches AS (
        select distinct test_messageq_table.master_id AS patient_id,
        test_patient_table.site_held_at as site_id
        from test_messageq_table 
        inner join test_patient_table 
        ON test_messageq_table.master_id = test_patient_table.entity_id 
        and site_held_at = ANY(sites) order by patient_id
    ),
    messages_for_patients AS(
        select * from test_messageq_table where master_id in 
            (select patient_msg_in_branches.patient_id 
                from patient_msg_in_branches)
    )
    select * from messages_for_patients;
end;

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Answer 2

Erw*_*ter 6

你写了“case close”，但我会重新打开。错的太多了……

数据库设计和测试设置

CREATE TABLE patient (
   patient_id   int PRIMARY KEY
 , site_held_at int NOT NULL
);

CREATE TABLE messageq (
   messageq_id  varchar PRIMARY KEY  -- varchar ?!
 , patient_id   int NOT NULL REFERENCES patient
 , message_body varchar NOT NULL
);

CREATE INDEX patient_site_idx ON patient(site_held_at);
CREATE INDEX messageq_patient_id_idx ON patient(patient_id); -- !!

INSERT INTO patient VALUES
  (1, 11111)
, (2, 11111)
, (3, 11111)
, (4, 11111)
, (5, 22222)
, (6, 22222)
, (7, 22222)
, (8, 22222)
, (9, 33333)
, (10, 33333)
, (11, 44444);

INSERT INTO messageq VALUES
  ('m1', 1, 'aaa1')
, ('m2', 1, 'aaa2')
, ('m3', 1, 'aaa3')
, ('m4', 1, 'aaa4')
, ('m5', 2, 'aaa5')
, ('m6', 2, 'aaa6')
, ('m7', 5, 'aaa7')
, ('m8', 8, 'aaa8')
, ('m9', 11, 'aaa9')
, ('m10', 11, 'bbb10');

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要点

简化名称以提高可读性。
不要使用非描述性的列名，如entity_id. 替换为有用的名称。
对具有相同内容的列使用相同的名称是一种很好的做法。使用patient_id在FK列messageq。
如果您varchar的消息队列中确实有一个PK，请使用实际varchar值进行测试。
简化INSERT语句。
在上添加索引messageq.patient_id。这对性能至关重要。

功能

CREATE OR REPLACE FUNCTION f_get_msg_from_sites(VARIADIC _id int[])
  RETURNS SETOF messageq AS 
$func$ 
   SELECT m.*
   FROM   patient  p
   JOIN   messageq m USING (patient_id)
   WHERE  p.site_held_at = ANY($1)
$func$ LANGUAGE sql;

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是的，仅此而已。
称呼：

SELECT * FROM f_get_msg_from_sites(11111, 44444);
SELECT * FROM f_get_msg_from_sites(22222);

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SQL Fiddle_{（在 pg9.2 上，pg9.3 已重载）}

要点

不需要 CTE（甚至两个）。在这里会浪费代码和时间。一个带有连接的简单查询就可以完成这项工作。
使用VARIADIC参数进行更简单的调用（可选）。
有关的：
- 如何在 plpgsql 中执行 WHERE x IN (val1, val2,...)
如果(patient_id int, site_held_at)在 table 中是唯一的patient，则DISTINCT在查询中不需要。否则添加它。

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