获得每天平均插入次数

Question

我有下表

CREATE TABLE public.listing
(
  id bigint NOT NULL DEFAULT nextval('listing_id_seq'::regclass),
  listing_url text NOT NULL,
  insert_time timestamp with time zone DEFAULT now(),
  CONSTRAINT listing_pkey PRIMARY KEY (id),
  CONSTRAINT listing_listing_url UNIQUE (listing_url)
)

如何获取过去一周每天插入的平均行数？

Answer 1

我认为您可以采取过去一周出现的记录数量，并将一周中的天数除以7：

select count(*) / 7
from public.listing
where insert_time > current_date - interval '7 days'   -- inserts happening in past week

Answer 2

从列表中选择COUNT（*）/ 7，其中insert_time介于＆＃39; 2016-09-01＆＃39;和＆＃39; 2016-09-07＆＃39; group by insert_time