PostgreSQL 调用函数返回带有 table 和附加列的记录集

PostgreSQL call function returning setof record with table and additional columns

我正在尝试调用一个函数,返回现有 table 的所有列 + 一些不相关的附加列,并使用以下语法检索返回的数据:

select *
from test_func(...)
as (a_table my_table_name, rows_count numeric);

函数格式如下:

CREATE OR REPLACE FUNCTION public.test_func(...)
 RETURNS SETOF record
 LANGUAGE plpgsql
AS $function$
    
DECLARE
    _sql VARCHAR;
begin
    
    _sql := 'SELECT mtn.*, count(*) over() as rows_count  
        from public.my_table_name mtn
        ... inner joins and other stuff';

    return query
    execute _sql using ..._sql params...;

END;
$function$
;

然而,它不起作用。我收到的错误:

ERROR: structure of query does not match function result type
  Detail: Returned type numeric does not match expected type "my_table_name" in column 1.

如果你的函数中的查询应该return一个my_table_name(一个“整行引用”),你应该这样写

SELECT mtn, count(*) OVER () ...