In my db i have many record, with start date and length of that time of period.
For example
id start_date lenght
1 2013-01-01 00:00:00 20
2 2013-02-30 00:00:00 10
3 2013-01-20 00:00:00 3
So i can easily get the end date.
Now if the user gave me any period of time, how can I control if that period is included in one of the time period that I have in the db?
Thank you.
You can get the list using a where clause and the date functions:
select *
from t
where XXX between start_date and date_add(start_date, interval length day);
EDIT:
The above is for one date. If the user gives two date, XXX and YYY, then this is what you want for any overlap:
select *
from t
where XXX <= date_add(start_date, interval length day) and
YYY >= start_date;
That is, the period the user gives you starts before the end of the interval and the period ends after the start of the interval.
Related
I have a column that is of type timestamp. I would like to dynamically group the results by random period time (it can be 10 seconds or even 5 hours).
Supposing, I have this kind of data:
Image
If the user provides 2 hours and wants to get the max value of the air_pressure, I would like to have the first row combined with the second one. The result should look like this:
date | max air_pressure
2022-11-22 00:00:00:000 | 978.81666667
2022-11-22 02:00:00:000 | 978.53
2022-11-22 04:00:00:000 | 987.23333333
and so on. As I mentioned, the period must be easy to change, because maybe he wants to group by days/seconds...
The functionality should work like function date_trunc(). But that can only group by minutes/seconds/hours, while I would like to group for arbitrary intervals.
Basically:
SELECT g.start_time, max(air_pressure) AS max_air_pressure
FROM generate_series($start
, $end
, interval '15 min') g(start_time)
LEFT JOIN tbl t ON t.date_id >= g.start_time
AND t.date_id < g.start_time + interval '15 min' -- same interval
GROUP BY 1
ORDER BY 1;
$start and $end are timestamps delimiting your time frame of interest.
Returns all time slots, and NULL for max_air_pressure if no matching entries are found for the time slot.
See:
Best way to count rows by arbitrary time intervals
Aside: "date_id" is an unfortunate column name for a timestamp.
I am using the DATEDIFF function to calculate the difference between my two timestamps.
payment_time = 2021-10-29 07:06:32.097332
trigger_time = 2021-10-10 14:11:13
What I have written is : date_diff('minute',payment_time,trigger_time) <= 15
I basically want the count of users who paid within 15 mins of the triggered time
thus I have also done count(s.user_id) as count
However it returns count as 1 even in the above case since the minutes are within 15 but the dates 10th October and 29th October are 19 days apart and hence it should return 0 or not count this row in my query.
How do I compare the dates in my both columns and then count users who have paid within 15 mins?
This also works to calculate minutes between to timestamps (it first finds the interval (subtraction), and then converts that to seconds (extracting EPOCH), and divides by 60:
extract(epoch from (payment_time-trigger_time))/60
In PostgreSQL, I prefer to subtract the two timestamps from each other, and extract the epoch from the resulting interval:
Like here:
WITH
indata(payment_time,trigger_time) AS (
SELECT TIMESTAMP '2021-10-29 07:06:32.097332',TIMESTAMP '2021-10-10 14:11:13'
UNION ALL SELECT TIMESTAMP '2021-10-29 00:00:14' ,TIMESTAMP '2021-10-29 00:00:00'
)
SELECT
EXTRACT(EPOCH FROM payment_time-trigger_time) AS epdiff
, (EXTRACT(EPOCH FROM payment_time-trigger_time) <= 15) AS filter_matches
FROM indata;
-- out epdiff | filter_matches
-- out ----------------+----------------
-- out 1616119.097332 | false
-- out 14.000000 | true
Problem
I have a table of records each containing id, in_datetime, and out_datetime. A record is considered "open" during the time between the in_datetime and out_datetime. I want to know how many time records were "open" for each minute of the day (regardless of date). For example, for the last 90 days I want to know how many records were "open" at 3:14 am, then 3:15 am, then 3:16 am, then... If no records were "open" at 2:00 am the query should return 0 or null instead of excluding the row, thus 1440 rows should always be returned (the number of minutes in a day). Datetimes are stored in UTC and need to be cast to a time zone.
Simplified example graphic
record_id | time_range
| 0123456789 (these are minutes past midnight)
1 | =========
2 | ===
3 | =======
4 | ===
5 | ==
______________________
result 3323343210
Desired output
time | count of open records at this time
00:00 120
00:01 135
00:02 132
...
23:57 57
23:58 62
23:59 60
No more than 1440 records would ever be returned as there are only 1440 minutes in the day.
What I've tried
1.) In a subquery, I currently generate a minutely series of times for the entire range of each time record. I then group those by time and get a count of the records per minute.
Here is a db-fiddle using my current query:
select
trs.minutes,
count(trs.minutes)
from (
select
generate_series(
DATE_TRUNC('minute', (time_records.in_datetime::timestamptz AT TIME ZONE 'America/Denver')),
DATE_TRUNC('minute', (time_records.out_datetime::timestamptz AT TIME ZONE 'America/Denver')),
interval '1 min'
)::time as minutes
from
time_records
) trs
group by
trs.minutes
This works but is quite inefficient and takes several seconds to run due to the size of my table. Additionally, it excludes times when no records were open. I think somehow I could use window functions to count the number of overlapping time records for each minute of the day, but I don't quite understand how to do that.
2.) Modifying Gordon Linoff's query in his answer below, I came to this (db-fiddle link):
with tr as (
select
date_trunc('minute', (tr.in_datetime::timestamptz AT TIME ZONE 'America/Denver'))::time as m,
1 as inc
from
time_records tr
union all
select
(date_trunc('minute', (tr.out_datetime::timestamptz AT TIME ZONE 'America/Denver')) + interval '1 minute')::time as m,
-1 as inc
from
time_records tr
union all
select
minutes::time,
0
from
generate_series(timestamp '2000-01-01 00:00', timestamp '2000-01-01 23:59', interval '1 min') as minutes
)
select
m,
sum(inc) as changes_at_inc,
sum(sum(inc)) over (order by m) as running_count
from
tr
where
m is not null
group by
m
order by
m;
This runs reasonably quickly, but towards the end of the day (about 22:00 onwards in the linked example) the values turn negative for some reason. Additionally, this query doesn't seem to work correctly with records with time ranges that cross over midnight. It's a step in the right direction, but I unfortunately don't understand it enough to improve on it further.
Here is a faster method. Generate "in" and "out" records for when something gets counted. Then aggregate and use a running sum.
To get all minutes, throw in a generate_series() for the time period in question:
with tr as (
select date_trunc('minute', (tr.in_datetime::timestamptz AT TIME ZONE 'America/Denver')) as m,
1 as inc
from time_records tr
union all
select date_trunc('minute', (tr.out_datetime::timestamptz AT TIME ZONE 'America/Denver')) + interval '1 minute' as m,
-1 as inc
from time_records tr
union all
select generate_series(date_trunc('minute',
min(tr.in_datetime::timestamptz AT TIME ZONE 'America/Denver')),
date_trunc('minute',
max(tr.out_datetime::timestamptz AT TIME ZONE 'America/Denver')),
interval '1 minute'
), 0
from time_records tr
)
select m,
sum(inc) as changes_at_inc,
sum(sum(inc)) over (order by m) as running_count
from tr
group by m
order by m;
I need to get the difference between 2 date time in minutes(Time difference in minutes). And the last difference will be calculated based on 6 PM of every date.
Sample data: need result of last column
User_Name Date Time difference in minutes
User 1 1/1/06 12:00 PM 30
user 2 1/1/06 12:30 PM 315
user 3 1/1/06 5:45 PM 15
Here the date will be always in same date and the last user date difference calculated based on default value 6PM. Assuming the dates of any user will not cross 6PM time.
Please suggest how to write the query for the same.
You could use the lead window function.
I assume your table is called mytable and the date column is mydate (it is a bad idea to call a column Date as it is a reserved word).
select user_name,
round((lead(mydate, 1, trunc(mydate)+18/24)
over (partition by trunc(mydate) order by mydate)
- mydate) *24*60) as difference
from mytable
I found the solution.. if its not correct let me know
SELECT User_name,created_date,
trunc(to_number((cast(nvl(lead (created_date,1) OVER (ORDER BY created_date),TRUNC(SYSDATE) + (19/24)) as date) - cast(created_date as date)))*24*60) as difference
FROM users;
I have a large set of data collected every 15 minutes. I am trying to select data between a certain time period and then within that time period divide it up by another date intervals. And within those intervals sum over a certain time period.
For example, I would like to be able to select data between 01/01/2009 and 01/01/2010 and group by date ranges 01/01/2009 - 05/01/2009, 05/02/2009 - 11/01/2009, 11/02/2009 - 01/01/2010 and then within each group select the data from time 00:00:01 - 12:00:00 and 12:00:01 - 23:59:59
SELECT SUM(Data.usage)AS sum
FROM Data.meter_id = Meter.id
WHERE Data.start_read >= '2009-01-01'
AND Data.end_read <= '2010-01-01 23:59:59'
GROUP BY date range? Not sure how to separate the data. Thanks
To group by date ranges, I often use case statements:
Group By Case
When start_read between '01/01/2009' and '05/01/2010' then 'Jan-Apr 09'
When start_read between '05/01/2009' and '11/01/2010' then 'May-Nov 09'
...etc