Question

请告诉我如何执行此操作我想在循环时选择多个列..

create or replace function insert_date_dimension("date" date)
 returns setof date as $$
declare
    dat date;
    start_date date;
    end_date date;
begin
    start_date := '2016/01/01';
    end_date := '2016/12/31';
    while start_date <= end_date loop
        --return next  start_date;
        select start_date,date_part('week',start_date),date_part('quarter',start_date),to_char(start_date, 'day'),to_char(start_date, 'month'),
        extract(year from current_date),extract(month from current_date);
        start_date:= start_date + interval  '1 day';
    end loop;
end;

$$ language plpgsql;

ERROR:  query "SELECT    start_date,date_part('week',start_date),date_part('quarter',start_date),to_char(start_date, 'day'),to_char(start_date, 'month'),
        extract(year from current_date),extract(month from current_date)" returned 7 columns

CONTEXT：PL / pgSQL函数insert_date_dimension（date）第11行在RETURN NEXT

Answer 1

发生错误是因为您必须在PL / pgSQL函数中使用SELECT ... INTO ...。此外，你忘了RETURN某事。

使用generate_series要容易得多;这样你甚至可能不需要定义一个函数，你可以使用INSERT INTO ... SELECT ...。

这是我写的功能：

CREATE OR REPLACE FUNCTION insert_date_dimension(
   OUT "date" date,
   OUT week integer,
   OUT quarter integer,
   OUT dayname text,
   OUT monthname text,
   OUT year integer,
   OUT month integer
) RETURNS SETOF RECORD STABLE LANGUAGE plpgsql AS
$$DECLARE
   dat date;
   start_date timestamp := '2016-01-01 00:00:00';
   end_date timestamp := '2016-12-31 00:00:00';
BEGIN
   RETURN QUERY SELECT
         d::date,
         date_part('week', d)::integer,
         date_part('quarter', d)::integer,
         to_char(d, 'day'),
         to_char(d, 'month'),
         date_part('year', d)::integer,
         date_part('month', d)::integer
      FROM generate_series(start_date, end_date, '1 day') d(d);
END;$$;

如何在postgresql中循环时选择多个列？

1 个答案: