如何从多个值中反对 row_to_json 和 array_agg

Question

我设法创建了一个 jsonb 输出，但是我需要将其作为对象

我当前的代码

create function extract_data()
  returns jsonb
as
$$
declare
  v_msgar text[];
  v_result jsonb;
  analyzer_test_full_desc character varying;
  data_reading character varying;
begin
  v_msgar := array['P|61||||^^||^^|U||||||||||||||||||||||||||<CR>',
                   'O|61|15^1^15|KK4002259|GLU^Glucose (GOD-POD Method)^^',
                   'R|170|AST^Aspartate Aminotransferase^^F|22.657989^^^^',
                   'R|171|ALP^Alkaline phosphatase^^F|107.636995^^^^',
                   'R|172|TP^Total Protein^^F|85.245151^^^^',
                   'R|173|TG^Triglycerides^^F|1.348633^^^^',
                   'R|174|HDL^HDL-Cholesterol^^F|1.238458^^^^',
                   'R|175|CHOL^Total Cholesterol^^F|5.073630^^^^',
                   'R|176|UA^Uric Acid^^F|309.705876^^^^',
                   'R|177|BUN^Urea^^F|4.412234^^^^'];

           SELECT split_part(items[3], '^', 1)
                  INTO  analyzer_test_full_desc
                FROM (
                  SELECT string_to_array(element, '|') as items
                 FROM unnest(v_msgar) as t(element)) t   
            WHERE items[1] = 'R';
        
            SELECT  split_part(items[4], '^', 1)
                  INTO data_reading
                FROM (
                  SELECT string_to_array(element, '|') as items
                 FROM unnest(v_msgar) as t(element)) t   
            WHERE items[1] = 'R';

            SELECT array_to_json(array_agg(row_to_json(t))) 
                 FROM (
                SELECT analyzer_test_full_desc as resultId, data_reading as resultValue
            ) t INTO v_result;
  
  return v_result;
end;  
$$
language plpgsql;

输出为

[{"resultid": "AST", "resultvalue": "22.657989"}]

我预计输出是这样的

[{"resultid": "AST", "resultvalue": "22.657989"},{"resultid": "ALP", "resultvalue": "107.636995"},{"resultid": "TP", "resultvalue": "85.245151"]

我尝试循环 select 语句，但仍然没有解决方案。

Answer 1

step-by-step demo:db<>fiddle

不一定需要存储过程，一个简单的查询就够了：

SELECT
    jsonb_agg(                                      -- 6
        jsonb_build_object(                         -- 5
            'resultid',
            split_part(parts[3],'^',1),             -- 4
            'resultvalue',
            split_part(parts[4],'^',1)
        )
    )
FROM mytable t,
    unnest(myarray) as elem,                        -- 1
    regexp_split_to_array(elem, '\|') as parts      -- 2
WHERE parts[1] = 'R'                                -- 3

将所有数组元素展开为一条记录
根据分隔符将元素拆分为新数组 |
过滤所有 R 个元素
取出预期的部分并检索 ^ 字符前的值
构建预期的 JSON 元素
将它们聚合成一个JSON数组

不过，如果你需要一个存储过程，当然可以将这个查询包装成一个：

create function extract_data()
  returns jsonb
as
$$
declare
  v_result jsonb;
begin

    SELECT
        ...
    INTO v_result
    FROM ...

    RETURN v_result;

end;  
$$
language plpgsql;

最后，您也可以将数组作为函数输入参数，而不是采用 table 输入：

create function extract_data(myarray text[])
  returns jsonb
as
$$
declare
  v_result jsonb;
begin

    SELECT
        jsonb_agg(
            jsonb_build_object(
                'resultid',
                split_part(parts[3],'^',1),
                'resultvalue',
                split_part(parts[4],'^',1)
            )
        )
    INTO v_result
    FROM unnest(myarray) as elem,
        regexp_split_to_array(elem, '\|') as parts
    WHERE parts[1] = 'R';

    RETURN v_result;

end;  
$$
language plpgsql;

Answer 2

您不需要 pl/pgsql 来执行此操作。在一个（内部）查询中提取您需要的数据部分，然后像这样聚合它们：

create or replace function extract_data(text[]) returns jsonb as
$$
select jsonb_agg(to_jsonb(t.*)) from 
(
 select split_part(split_part(arr, '|', 3), '^', 1) as "resultId", 
        split_part(split_part(arr, '|', 4), '^', 1) as "resultValue"
 from unnest() arr
 where split_part(arr, '|', 1) = 'R'
) t;
$$ language sql;

select extract_data(array[
 'P|61||||^^||^^|U||||||||||||||||||||||||||<CR>',
 'O|61|15^1^15|KK4002259|GLU^Glucose (GOD-POD Method)^^',
 'R|170|AST^Aspartate Aminotransferase^^F|22.657989^^^^',
 'R|171|ALP^Alkaline phosphatase^^F|107.636995^^^^',
 'R|172|TP^Total Protein^^F|85.245151^^^^',
 'R|173|TG^Triglycerides^^F|1.348633^^^^',
 'R|174|HDL^HDL-Cholesterol^^F|1.238458^^^^',
 'R|175|CHOL^Total Cholesterol^^F|5.073630^^^^',
 'R|176|UA^Uric Acid^^F|309.705876^^^^',
 'R|177|BUN^Urea^^F|4.412234^^^^'
]);

为了使函数可重用，将数据数组作为参数传递，而不是将其硬编码在函数体内。

如何从多个值中反对 row_to_json 和 array_agg

How to object in row_to_json and array_agg from multiple value

json

postgresql

stored-procedures

jsonb

array-agg