前置条件：需要维护一张节假日日期表。例如创建holiday表保存当年假期日期

CREATE TABLE `holiday` (
	`id` BIGINT(10) ZEROFILL NOT NULL DEFAULT 0,
	`day` TIMESTAMP NULL DEFAULT NULL,
	PRIMARY KEY (`id`)
)
COMMENT='假期表'
COLLATE='utf8mb4_0900_ai_ci'
;

返回日期为xx日xx时xx分格式，可以在此基础上调整格式

-- FUNCTION: public.get_timedelay(timestamp with time zone, timestamp with time zone)

-- DROP FUNCTION IF EXISTS public.get_timedelay(timestamp with time zone, timestamp with time zone);

CREATE OR REPLACE FUNCTION public.get_timedelay(
	starttime timestamp with time zone,
	endtime timestamp with time zone)
    RETURNS text
    LANGUAGE 'plpgsql'
    COST 100
    VOLATILE PARALLEL UNSAFE
AS $BODY$
DECLARE
	 v_return  varchar;--返回间隔时间 xx日xx时xx分
	 v_minute  integer;--间隔分钟
	 v_hour integer;
	 v_temp_minute integer;
	 v_temp_hour integer;
	 v_day integer; --间隔天数
	 v_all numeric;
	 v_counter integer;
	 v_end_weekend integer;
	 v_weekend integer;--周一_周日 1_6_0
	 v_holiday numeric;--匹配节假日天数
	 v_is_weekend boolean; --是否周末
	 v_is_holiday boolean; --是否节假日
BEGIN
		--计算时间间隔天数
		select ceil(DATE_PART('epoch', endtime::timestamp - starttime::TIMESTAMP)/60/60/24) into v_all;
		--减去周末、节假日
		v_end_weekend := cast(EXTRACT(DOW FROM (endtime)) as int);
		v_day := 0;
		v_hour := 0;
		v_minute := 0;
		v_counter := 0;
		while v_counter <= v_all loop
		   v_temp_minute := 0;
		   v_temp_hour  := 0;
		   v_is_weekend := FALSE;
		   v_is_holiday := FALSE;
			--判断该日期为周几
			v_weekend := v_end_weekend-v_counter%7;
			if v_weekend < 0 then
			   v_weekend := v_weekend + 7;
			end if;
			if v_weekend = 6 or v_weekend = 0 then
				v_is_weekend := true;
			end if;
			--判断该日期是否为节假日
			--日期表
			SELECT COUNT(*) FROM holiday WHERE Date(endtime) - DATE(day) - v_counter  = 0 INTO v_holiday;
			if v_is_weekend = false and v_holiday > 0 then
				v_is_holiday := true;
			end if;
			--累计时长
			if v_is_weekend = false AND v_is_holiday = false then
			   if v_counter = 0  then
			      v_minute := cast(date_part('minute', endtime::TIMESTAMP) as int);
			      v_hour := cast(date_part('hour', endtime::TIMESTAMP) as int);
			   elseif v_counter = v_all then
			      v_temp_minute := 60 - cast(date_part('minute', endtime::TIMESTAMP) as int);
			      v_temp_hour := 23 - cast(date_part('hour', endtime::TIMESTAMP) as int);
			      v_minute := (v_minute+v_temp_minute) % 60;
			      v_temp_hour := v_temp_hour+FLOOR((v_minute+v_temp_minute)/60);
			      v_hour := (v_hour+v_temp_hour) % 24;
			      v_day := v_day + FLOOR((v_hour+v_temp_hour) / 24);
				else
			   	v_day := v_day + 1;
			   end if;
			end if;
			v_counter:= v_counter+1;
		end loop;
		--处理返回日期
		v_return := '';
	
		--返回日、时、分方案
		if v_day > 0 then
		  v_return := concat(v_return, v_day,'日');
		end if;
		if v_hour > 0 then
		  v_return := concat(v_return, v_hour,'时');
		end if;
		if v_minute > 0 then
		  v_return := concat(v_return,v_minute,'分');
		end if;
	 
  RETURN v_return;
	
	EXCEPTION 
	WHEN OTHERS THEN
		RETURN SQLERRM;
	
END;
$BODY$;

ALTER FUNCTION public.get_timedelay(timestamp with time zone, timestamp with time zone)
    OWNER TO postgres;