计算两个日期之间的工作日数

Question

我正在尝试获取 plpgsql 中两个日期之间的工作日数。以下是我的代码：

CREATE FUNCTION weekdays(DATE, DATE) RETURNS INTEGER AS
$$
DECLARE
    d date := ;
    weekdays integer := 0
BEGIN

LOOP
    IF select extract(dow from date d) != 6 or select extract(dow from date d) != 0
      weekdays := weekdays +1
    END IF
    d := d + 1;
    EXIT WHEN d > ;
END LOOP;
RETURN weekdays;
END;
$$
LANGUAGE 'plpgsql' IMMUTABLE;

但是，我不断收到以下错误：

Unterminated dollar quote started at position 56 in SQL
CREATE FUNCTION weekdays(DATE, DATE) RETURNS INTEGER AS $$ DECLARE d date := .
Expected terminating $$

Answer 1

错误是由于 weekdays integer := 0; 之后缺少 ;。加上更多此类错误。这将有效 :

CREATE  OR REPLACE FUNCTION weekdays(date, date)
  RETURNS integer AS
$func$
DECLARE
   d        date := ;
   weekdays int  := 0;
BEGIN
   LOOP
      IF extract(isodow from d) < 6 THEN  -- simpler
         weekdays := weekdays + 1;
      END IF;
      d := d + 1;
      EXIT WHEN d > ;
   END LOOP;
   RETURN weekdays;
END
$func$  LANGUAGE plpgsql IMMUTABLE;

但我建议使用 更简单、更快速的 SQL 函数 ：

CREATE OR REPLACE FUNCTION weekdays_sql(date, date)
  RETURNS integer AS
$func$
SELECT count(*)::int
FROM   generate_series(, , interval '1d') d
WHERE  extract(isodow FROM d) < 6;
$func$  LANGUAGE sql IMMUTABLE;

可能会进一步提高大范围的性能。相关：

How to count days except Sundays between two dates in Postgres?
Calculate working hours between 2 dates in PostgreSQL

Answer 2

不需要循环，用算术就能找到答案

CREATE OR REPLACE FUNCTION public.weekdays(s date, e date) RETURNS integer
 LANGUAGE plpgsql
 IMMUTABLE
AS $function$
DECLARE
  sd int = extract (isodow from s-1); 
  ed int = extract (isodow from e); 
BEGIN
   RETURN - case sd when 7 then 5 when 6 then 5 else sd end 
          + case ed when 7 then 5 when 6 then 5 else ed end 
          + (e-ed-s+sd+1)/7*5;
END;
$function$;

Answer 3

在我看来没那么复杂，而且也能正常工作。

CREATE OR REPLACE FUNCTION weekdays
(
date1 DATE,
date2 DATE
)
RETURNS INTEGER AS $$
DECLARE weekdays INTEGER;
BEGIN

SELECT COUNT(extract(ISODOW FROM series)) INTO weekdays
FROM generate_series(date1::date, date2::date, '1 day'::interval) series
WHERE extract(ISODOW FROM series) < 6;

RETURN weekdays;

END;
$$ LANGUAGE plpgsql;

计算两个日期之间的工作日数

Counting number of weekdays between two dates

postgresql

time-series

plpgsql