sql 从日期和频率字符串评估下一个法国工作日
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-- -----------------------------------
-- FUNCTION: easter_date
-- -----------------------------------
CREATE OR REPLACE FUNCTION easter_date(year integer)
RETURNS timestamp as $$
DECLARE
g integer := year % 19;
c integer := (year/100)::int;
h integer := ((c - (c/4)::int - ((8*c+13)/25)::int + 19*g + 15) % 30)::int;
i integer := h - (h/28)::int * (1 - (h/28)::int * (29/(h + 1))::int * ((21 - g)/11)::int);
j integer := (year + (year/4)::int + i + 2 - c + (c/4)::int) % 7;
l integer := i - j;
m integer := 3 + ((l + 40)/44)::int;
d integer := l + 28 - 31 * (m/4)::int;
easter varchar(10) := year::text || '-' || m::text || '-' || d::text;
BEGIN
return easter::timestamp;
END;
$$ language plpgsql;
-- -----------------------------------
-- FUNCTION: get_holidays
-- -----------------------------------
CREATE OR REPLACE FUNCTION get_holidays()
RETURNS table(holiday date) AS $$
DECLARE
year text := extract(year from current_date);
next text := (year::int+1)::text;
easter1 timestamp := easter_date(year::int);
easter2 timestamp := easter_date(next::int);
BEGIN
return query
select t.*
from unnest(array[
-- current year
(year||'-01-01')::date, (year||'-05-01')::date,
(year||'-05-08')::date, (year||'-07-14')::date,
(year||'-08-15')::date, (year||'-11-01')::date,
(year||'-11-11')::date, (year||'-12-25')::date,
easter1::date + 1, easter1::date + 39, easter1::date + 50,
-- next year
(next||'-01-01')::date, (next||'-05-01')::date,
(next||'-05-08')::date, (next||'-07-14')::date,
(next||'-08-15')::date, (next||'-11-01')::date,
(next||'-11-11')::date, (next||'-12-25')::date,
easter2::date + 1, easter2::date + 39, easter2::date + 50
]) t;
END;
$$ language plpgsql;
-- -----------------------------------
-- FUNCTION: evaluate_next_run
-- -----------------------------------
CREATE OR REPLACE FUNCTION evaluate_next_run(last_run timestamp with time zone, rule text)
RETURNS timestamp with time zone AS $$
DECLARE
options text;
nextday text;
daily interval := '1 day'::interval;
monthly interval := '1 mon'::interval;
next_run timestamp;
BEGIN
CASE substring($2 from 'freq=(\w+)')
WHEN 'daily' THEN
options := substring($2 from 'days=([\w,]+)');
select min(l.next_runs) into next_run from (
select s::timestamp as next_runs
from generate_series($1 + daily, $1 + daily * 7, daily) s
where options like '%' || extract(dow from s) || '%'
except select holiday + ($1)::time from get_holidays()
) l;
WHEN 'monthly' THEN
options := substring($2 from 'days=-([\d]+)');
IF options IS NOT NULL THEN
select min(next_runs) into next_run from (
select row_number() over (
partition by extract(mon from next_runs)
order by extract(day from next_runs) desc
) as rownum, next_runs
from (
select s::timestamp as next_runs
from generate_series($1 + daily, $1 + monthly * 2 - daily, daily) s
where extract(dow from s) in (1,2,3,4,5)
except select holiday + ($1)::time from get_holidays()
) l1
) l2 where rownum = options::int;
ELSE
options := substring($2 from 'days=([\d,]+)');
select min(t.day) into nextday
from unnest(string_to_array(options, ',')) as t(day)
where t.day::int > extract(day from $1);
IF nextday IS NULL THEN
nextday := split_part(options, ',', 1);
END IF;
select min(next_runs) into next_run from (
select
row_number() over (order by extract(mon from s) desc, extract(day from s)) as rownum,
s::timestamp as next_runs
from generate_series($1, $1 + monthly - daily, daily) s
) l where l.rownum = nextday::int;
next_run := evaluate_next_run(next_run - daily, 'freq=daily; days=1,2,3,4,5');
END IF;
END CASE;
return next_run;
END;
$$ language plpgsql;
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