子查询返回的多行用作表达式但仅在函数中

Question

当我使用一个函数时它给出了提到的错误，但是当单独使用相同的代码时它工作得很好。哪里出了问题？

Fiddle 函数：https://dbfiddle.uk/?rdbms=postgres_12&fiddle=c4b0c8a59d2bd851284ed624ab1c335d

摆弄干净select：https://dbfiddle.uk/?rdbms=postgres_12&fiddle=7ccca6c70061aff1f6c394815aa8e9b1

示例数据：

create table report
(report_day date,
 tickets_no integer,
 tickets_stake numeric,
 promo_tickets_no integer,
 promo_tickets_stake numeric,
 group_id integer);
 
 insert into report
 values
 ('2020-07-20',12,569.6, 2, 44,1),
 ('2020-07-20',61,2000, 5, 260,2),
  ('2020-07-21',35,1244.2, 11, 250,1),
  ('2020-07-21',100,2500.5, 29, 575,2),
   ('2020-07-22',66,2511.8, 23, 670,1),
   ('2020-07-22',125,3358.2, 50, 990,2);

CREATE OR REPLACE FUNCTION report(arguments json)
  RETURNS json AS
$BODY$
     
DECLARE 
        
    dateFrom date;
    dateTo date;
        selectedType integer;
BEGIN 
        
    dateFrom := cast(arguments->>'dateFrom' as date);
    dateTo := cast(arguments->>'dateTo' as date);
    selectedType := cast(arguments->>'selectedType' as integer);

RETURN (
    WITH full_data as (
 with tickets as (
  select 
    report_day
  , sum(tickets_no) as tickets_no
  , sum(tickets_stake) as tickets_stake
  FROM report
  WHERE selectedType = 0
  AND report_day between dateFrom and dateTo
  GROUP BY 1)
  
, promo_tickets as (
  select 
    report_day
  , sum(promo_tickets_no) as promo_tickets_no
  , sum(promo_tickets_stake) as promo_tickets_stake
  FROM report
  WHERE selectedType = 1
  AND report_day between dateFrom and dateTo
  GROUP BY 1)
  
  select 
    t.report_day 
  , sum(coalesce(t.tickets_no,0) + coalesce(pt.promo_tickets_no,0)) as tickets_no                             
  , sum(coalesce(t.tickets_stake,0) + coalesce(pt.promo_tickets_stake,0)) as tickets_no
  FROM tickets t
  LEFT JOIN promo_tickets pt on t.report_day = pt.report_day                                    
   GROUP BY 1
   ORDER BY 1)
        
select row_to_json(full_data) from full_data
);

END;
$BODY$
  LANGUAGE plpgsql VOLATILE
  COST 100;
  
  select * from report(json_build_object('dateFrom', '2020-07-20', 'dateTo', '2020-07-22','selectedType', 0 ))

Answer 1

因为您正试图从一个函数中 return 多行，而本应只 return 编辑一行。向您的函数添加一个参数，最好是一个主键列（我想 tickets_no ），例如

CREATE OR REPLACE FUNCTION report(arguments json, i_tickets_no int)

并将查询重写为

WITH full_data AS
 (WITH tickets AS
     (SELECT report_day,
            SUM(tickets_no) AS tickets_no,
            SUM(tickets_stake) AS tickets_stake
       FROM report
      WHERE selectedType = 0
        AND report_day BETWEEN dateFrom AND dateTo
        AND tickets_no = i_tickets_no
      GROUP BY 1),
    promo_tickets as
     (select report_day,
            SUM(promo_tickets_no) as promo_tickets_no,
            SUM(promo_tickets_stake) as promo_tickets_stake
       FROM report
      WHERE selectedType = 1
        AND report_day BETWEEN dateFrom AND dateTo
      GROUP BY 1)
    
    select t.report_day,
           SUM(COALESCE(t.tickets_no, 0) + COALESCE(pt.promo_tickets_no, 0)) AS tickets_no,
           SUM(COALESCE(t.tickets_stake, 0) +
               COALESCE(pt.promo_tickets_stake, 0)) AS tickets_no
      FROM tickets t
      LEFT JOIN promo_tickets pt
        ON t.report_day = pt.report_day
     GROUP BY 1
     ORDER BY 1)

并通过添加第二个参数来调用。

Demo

Answer 2

如果您希望您的函数像您的查询一样return 报告对象数组，请更改此部分：

select row_to_json(full_data) from full_data

要将行聚合到一个数组中：

select json_agg(row_to_json(full_data)) from full_data

如果你想让函数return多行，那么你需要做两个改变：

CREATE OR REPLACE FUNCTION report(arguments json)
  RETURNS table (row_to_json json) AS

对于return：

RETURN QUERY (
    WITH full_data as (

已更新fiddle here.

子查询返回的多行用作表达式但仅在函数中

More than one row returned by a subquery used as an expression but only in function

sql

postgresql

stored-functions