sql查询分别每小时计数人

Question

I have a table which has theses fields:

id | person_id | start_time | end_time | status

I want to get number of people which exists in each hour in a specific day, something like below pseudo code:

select count(person) from table where dow of end_time=day and end_time >= hour and start_time < hour+1 for hour in working hours of organization and day is a certain day of week

If it would be possible to have a temporary table which consists of hours of a day may be the following solution is a solution:

select t.h, count(s.id)
from
session s cross join (temperoray table with one column of hours in a day as t)
where
s.start_time < (t.h + 1) and s.end_time > t.h
group by
t.h

But I do not know a command which could create a temporary table as I needed.

I found this question which is very similar to what I want but all of its solution is based on group by which I do not think makes any sense in my case because parts of each group has common items, eg, a person could count as person in hour 11 and person in hour 12 and 13.

I hope that I can find a way that gets me a table like this:

hour     |number of persons
10       |2
11       |0
12       |3
13       |1
...

Notice that it may possible to have some day with zero number of persons.

Example:

  id  | status |            start_time            |             end_time             | branch_id | person_id | session_type 
------+--------+----------------------------------+----------------------------------+-----------+-----------+--------------
 2675 | FI     | 2018-04-23 10:30:50.939693+04:30 | 2018-04-23 12:31:39.340692+04:30 |         1 |      1085 | IN
 2676 | FI     | 2018-04-23 11:47:06.683374+04:30 | 2018-04-23 13:23:52.659714+04:30 |         1 |      2722 | IN
 2677 | FI     | 2018-04-23 11:47:59.341765+04:30 | 2018-04-23 13:25:46.339266+04:30 |         1 |      2721 | IN
 2678 | FI     | 2018-04-23 11:58:34.854222+04:30 | 2018-04-23 13:25:55.08795+04:30  |         1 |      2723 | IN
 2679 | FI     | 2018-04-23 12:27:58.817234+04:30 | 2018-04-23 13:12:28.278699+04:30 |         1 |      2724 | IN
 2680 | FI     | 2018-04-23 12:30:36.552407+04:30 | 2018-04-23 12:30:54.088159+04:30 |         1 |      2725 | IN
 2681 | FI     | 2018-04-23 14:55:50.886725+04:30 | 2018-04-23 16:08:27.076629+04:30 |         1 |        25 | IN
 2682 | FI     | 2018-04-23 15:06:30.443347+04:30 | 2018-04-23 15:52:20.128546+04:30 |         1 |      2653 | IN
 2683 | FI     | 2018-04-23 15:21:57.979387+04:30 | 2018-04-23 16:16:09.289267+04:30 |         1 |      2580 | IN
 2684 | FI     | 2018-04-23 15:26:18.057999+04:30 | 2018-04-23 16:02:44.704133+04:30 |         1 |      2726 | IN
 2685 | FI     | 2018-04-23 16:50:10.2957+04:30   | 2018-04-23 17:23:01.732404+04:30 |         1 |      2727 | IN
 2686 | FI     | 2018-04-23 16:52:28.474299+04:30 | 2018-04-23 17:23:51.013318+04:30 |         1 |      2728 | IN
 2687 | FI     | 2018-04-23 16:58:05.796563+04:30 | 2018-04-23 17:33:03.259335+04:30 |         1 |      1646 | IN
 2688 | FI     | 2018-04-23 17:50:02.738009+04:30 | 2018-04-23 18:43:27.152203+04:30 |         1 |      2729 | IN
 2689 | FI     | 2018-04-23 18:47:12.19468+04:30  | 2018-04-23 19:25:46.606731+04:30 |         1 |      2730 | IN
 2690 | FI     | 2018-04-23 19:18:32.922065+04:30 | 2018-04-23 20:11:26.703693+04:30 |         1 |      2408 | IN
 2691 | FI     | 2018-04-23 19:18:53.133712+04:30 | 2018-04-23 19:56:47.702305+04:30 |         1 |      2409 | IN
 2692 | FI     | 2018-04-23 19:21:00.348889+04:30 | 2018-04-23 20:24:25.882451+04:30 |         1 |      2731 | IN
 2693 | FI     | 2018-04-23 19:30:05.908247+04:30 | 2018-04-23 20:12:36.627888+04:30 |         1 |      2591 | IN
 2694 | FI     | 2018-04-23 19:36:02.700379+04:30 | 2018-04-23 20:13:35.146002+04:30 |         1 |      2732 | IN
 2695 | FI     | 2018-04-23 19:50:15.13214+04:30  | 2018-04-23 20:09:37.168147+04:30 |         1 |      2491 | IN
 2696 | FI     | 2018-04-23 19:51:54.754169+04:30 | 2018-04-23 20:09:59.029376+04:30 |         1 |      2733 | IN
 2697 | FI     | 2018-04-23 19:53:13.529475+04:30 | 2018-04-23 20:09:49.229139+04:30 |         1 |      2734 | IN
 2698 | FI     | 2018-04-23 19:59:27.70488+04:30  | 2018-04-23 20:21:47.862433+04:30 |         1 |      1762 | IN
 2699 | FI     | 2018-04-23 19:59:57.86605+04:30  | 2018-04-23 20:22:05.171377+04:30 |         1 |      1761 | IN
 2700 | FI     | 2018-04-23 20:24:21.212784+04:30 | 2018-04-23 20:47:31.854373+04:30 |         1 |      2735 | IN
 2701 | FI     | 2018-04-23 21:58:57.308547+04:30 | 2018-04-23 22:43:20.075321+04:30 |         1 |      1705 | IN
 2702 | FI     | 2018-04-23 21:59:44.974384+04:30 | 2018-04-23 22:43:45.946989+04:30 |         1 |      1704 | IN
 2703 | FI     | 2018-04-23 22:10:20.991216+04:30 | 2018-04-23 22:40:51.16409+04:30  |         1 |      2711 | IN

And I which to get results for this day as below:

hour   | number
10     | 1
11     | 4
12     | 6
13     | 4
14     | 1
15     | 4
16     | 6
17     | 4
18     | 2
19     | 11
20     | 10
21     | 2
22     | 3

Answer 1

If I understand correct

you need to use generate_series function to create 24 hour then left join it.

You can add some condition on Where clause.

Get by Hour

SELECT    gs.hours, 
          Sum( 
          CASE 
                    WHEN start_time IS NOT NULL THEN 1 
                    WHEN end_time IS NOT NULL THEN 1 
                    ELSE 0 
          END ) AS "count" 
FROM      ( 
                 SELECT hours 
                 FROM   Generate_series(1,24) AS gs(hours) ) gs 
LEFT JOIN 
          ( 
                 SELECT *, 
                        Generate_series(start_time::timestamp, end_time::timestamp, '1 hours') invhour
                 FROM   t )t 
ON        gs.hours = To_char(t.invhour,'HH24')::integer 
GROUP BY  gs.hours

Get by Hour and Date

SELECT    To_char(t.invhour,'yyyy-MM-dd') AS "dates", 
          gs.hours, 
          Sum( 
          CASE 
                    WHEN start_time IS NOT NULL THEN 1 
                    WHEN end_time IS NOT NULL THEN 1 
                    ELSE 0 
          END ) AS "count" 
FROM      ( 
                 SELECT hours 
                 FROM   Generate_series(1,24) AS gs(hours) ) gs 
LEFT JOIN 
          ( 
                 SELECT *, 
                        Generate_series(start_time::timestamp, end_time::timestamp, '1 hours') invhour
                 FROM   t )t 
ON        gs.hours = To_char(t.invhour,'HH24')::integer 
GROUP BY  gs.hours, 
          to_char(t.invhour,'yyyy-MM-dd')

sqlfiddle: http://sqlfiddle.com/#!17/717fa/1

generate_series

Answer 2

You will need to create a set for the 24 hours, then do a left join and a group by hour.

Someone here has suggested using generate_series in a subquery, but personally I think recursive ctes are a little nicer for creating ranges. This way you can keep the series set outside the main query, making it a little easier to understand and maintain.

; WITH RECURSIVE Hours AS 
(
   SELECT 1 AS hour
   UNION ALL 
   SELECT hour + 1 FROM Hours WHERE Hour < 24
)

SELECT hour, COUNT(person_id)
FROM Hours
LEFT JOIN T on hour BETWEEN extract(hour from start_time) AND extract(hour from end_time)
GROUP BY hour
ORDER BY hour

http://sqlfiddle.com/#!17/717fa/12/0

Answer 3

Using the generate_series from D-Shih's answer I get the following solutions.

This first solution shows all hours when at least one person was working.

select Hour, count(1) as "Users"
from generate_series(1,24) as gs (Hour)
join Log as l
  on  date_part('hour',l.TimeFrom) <= gs.Hour
  and date_part('hour',l.TimeTo) >= gs.Hour
group by Hour
order by Hour;

If you also need the hours when nobody was working, use a left join . This requires a change to the count() to only count when a record is found.

select Hour, count(case when l.UserId is not null then 1 end) as "Users"
from generate_series(1,24) as gs (Hour)
left join Log as l
  on  date_part('hour',l.TimeFrom) <= gs.Hour
  and date_part('hour',l.TimeTo) >= gs.Hour
group by Hour
order by Hour;

See this SQL Fiddle for some example data and output.

Answer 4

Look at this article which walks through creating a Temp table in PostgreSQL (I am a SQL server person).

Have one column which is the hours of the day and I think your method of joining it to your table would work.

It also depends on your data in that table too. Can you provide a top 1 row data to get an idea of how it looks like? You might not even need the temp table.