Calculating Starting Date Across Multiple Date Ranges - sql

I have a SQL question which I have not been able to solve for a while now. I have looked everywhere without luck. I spent a lot of time looking through StackOverflow and thought someone here might be able to help.
I need to be able to determine a starting date x number of days back across multiple ranges. For example:
Range || Ending Date of Range (date) || Number of Days in Range (int)
1 || 2/20/2013 || 44
2 || 9/5/2014 || 75
3 || 3/25/2016 || 20
I have 3 ranges lasting various amounts of time with the ending date for each. The date ranges never overlap. I need to count a specific number, let's say 100 days, back in the range. In the example above. The answer would be 2/15/13.
20 + 75 = 95 days. 100 - 95 = 5 days. So 5 days back from 2/20/2013 is 2/15/2013.
Does anyone know how I might go about accomplishing this in a SQL query?
I believe the best way involves adding the ranges together until the sum passes the desired number (100) then taking the difference just prior (95) and subtracting it from (100) which would give me (5) from there its just simple date math. I could easily do this with any programming language but with SQL I am struggling.
Really what I need help with is coming up with (5) and the correct end date (2/20/2013). I can handle the date math from there.
I would appreciate any guidance on how I might a go about accomplishing this. Thanks in advance.


I tried this in Sybase:
SELECT
max(CASE WHEN total_days >= chosen_days THEN end_date END)
-
min(CASE WHEN total_days < chosen_days THEN chosen_days - total_days ELSE chosen_days END)
FROM
(
SELECT a.end_date, sum(b.days_in_range) AS total_days, 100 AS chosen_days
FROM test AS a JOIN test AS b ON a.end_date <= b.end_date
GROUP BY a.end_date
) AS x

Related

Data aggregation by sliding time periods

[Query and question edited and fixed thanks to comments from #Gordon Linoff and #shawnt00]
I recently inherited a SQL query that calculates the number of some events in time windows of 30 days from a log database. It uses a CTE (Common Table Expression) to generate the 30 days ranges since '2019-01-01' to now. And then it counts the cases in those 30/60/90 days intervals. I am not sure this is the best method. All I know is that it takes a long time to run and I do not understand 100% how exactly it works. So I am trying to rebuild it in an efficient way (maybe as it is now is the most efficient way, I do not know).
I have several questions:
One of the things I notice is that instead of using DATEDIFF the query simply substracts a number of days from the date.Is that a good practice at all?
Is there a better way of doing the time comparisons?
Is there a better way to do the whole thing? The bottom line is: I need to aggregate data by number of occurrences in time periods of 30, 60 and 90 days.
Note: LogDate original format is like 2019-04-01 18:30:12.000.
DECLARE #dt1 Datetime='2019-01-01'
DECLARE #dt2 Datetime=getDate();
WITH ctedaterange
AS (SELECT [Dates]=#dt1
UNION ALL
SELECT [dates] + 30
FROM ctedaterange
WHERE [dates] + 30<= #dt2)
SELECT
[dates],
lt.Activity, COUNT(*) as Total,
SUM(CASE WHEN lt.LogDate <= dates and lt.LogDate > dates - 90 THEN 1 ELSE 0 END) AS Activity90days,
SUM(CASE WHEN lt.LogDate <= dates and lt.LogDate > dates - 60 THEN 1 ELSE 0 END) AS Activity60days,
SUM(CASE WHEN lt.LogDate <= dates and lt.LogDate > dates - 30 THEN 1 ELSE 0 END) AS Activity30days
FROM ctedaterange AS cte
JOIN (SELECT Activity, CONVERT(DATE, LogDate) as LogDate FROM LogTable) AS lt
ON cte.[dates] = lt.LogDate
group by [dates], lt.Activity
OPTION (maxrecursion 0)
Sample dataset (LogTable):
LogDate, Activity
2020-02-25 01:10:10.000, Activity01
2020-04-14 01:12:10.000, Activity02
2020-08-18 02:03:53.000, Activity02
2019-10-29 12:25:55.000, Activity01
2019-12-24 18:11:11.000, Activity03
2019-04-02 03:33:09.000, Activity01
Expected Output (the output does not reflect the data shown above for I would need too many lines in the sample set to be shown in this post)
As I said above, the bottom line is: I need to aggregate data by number of occurrences in time periods of 30, 60 and 90 days.
Activity, Activity90days, Activity60days, Activity30days
Activity01, 3, 0, 1
Activity02, 1, 10, 2
Activity03, 5, 1, 3
Thank you for any suggestion.

SQL Server doesn't yet have the option to range over values of the window frame of an analytic function. Since you've generated all possible dates though and you've already got the counts by date, it's very easy to look back a specific number of (aggregated) rows to get the right totals. Here is my suggested expression for 90 days:
sum(count(LogDate)) over (
partition by Activity order by [dates]
with rows between 89 preceding and current row
)

Multiple aggregate sums from different conditions in one sql query

Whereas I believe this is a fairly general SQL question, I am working in PostgreSQL 9.4 without an option to use other database software, and thus request that any answer be compatible with its capabilities.
I need to be able to return multiple aggregate totals from one query, such that each sum is in a new row, and each of the groupings are determined by a unique span of time, e.g. WHERE time_stamp BETWEEN '2016-02-07' AND '2016-02-14'. The number of records that satisfy there WHERE clause is unknown and may be zero, in which case ideally the result is "0". This is what I have worked out so far:
(
SELECT SUM(minutes) AS min
FROM downtime
WHERE time_stamp BETWEEN '2016-02-07' AND '2016-02-14'
)
UNION ALL
(
SELECT SUM(minutes)
FROM downtime
WHERE time_stamp BETWEEN '2016-02-14' AND '2016-02-21'
)
UNION ALL
(
SELECT SUM(minutes)
FROM downtime
WHERE time_stamp BETWEEN '2016-02-28' AND '2016-03-06'
)
UNION ALL
(
SELECT SUM(minutes)
FROM downtime
WHERE time_stamp BETWEEN '2016-03-06' AND '2016-03-13'
)
UNION ALL
(
SELECT SUM(minutes))
FROM downtime
WHERE time_stamp BETWEEN '2016-03-13' AND '2016-03-20'
)
UNION ALL
(
SELECT SUM(minutes)
FROM downtime
WHERE time_stamp BETWEEN '2016-03-20' AND '2016-03-27'
)
Result:
min
---+-----
1 | 119
2 | 4
3 | 30
4 |
5 | 62
6 | 350
That query gets me almost the exact result that I want; certainly good enough in that I can do exactly what I need with the results. Time spans with no records are blank but that was predictable, and whereas I would prefer "0" I can account for the blank rows in software.
But, while it isn't terrible for the 6 weeks that it represents, I want to be flexible and to be able to do the same thing for different time spans, and for a different number of data points, such as each day in a week, each week in 3 months, 6 months, each month in 1 year, 2 years, etc... As written above, it feels as if it is going to get tedious fast... for instance 1 week spans over a 2 year period is 104 sub-queries.
What I'm after is a more elegant way to get the same (or similar) result.
I also don't know if doing 104 iterations of a similar query to the above (vs. the 6 that it does now) is a particularly efficient usage.
Ultimately I am going to write some code which will help me build (and thus abstract away) the long, ugly query--but it would still be great to have a more concise and scale-able query.

In Postgres, you can generate a series of times and then use these for the aggregation:
select g.dte, coalesce(sum(dt.minutes), 0) as minutes
from generate_series('2016-02-07'::timestamp, '2016-03-20'::timestamp, interval '7 day') g(dte) left join
downtime dt
on dt.timestamp >= g.dte and dt.timestamp < g.dte + interval '7 day'
group by g.dte
order by g.dte;

How to get a SUM of a DATEDIFF but provide cut-off at 24 hours IF a single day is specified

This is actually my first question on stackoverflow, so I sincerely apologize if I am confusing or unclear.
That being said, here is my issue:
I work at a car manufacturing company and we have recently implemented the ability to track when our machines are idle. This is done by assessing the start and end time of the event called "idle_start."
Right now, I am trying to get the SUM of how long a machine is idle. Now, I figured this out BUT, some of the idle_times are LONGER than 24 hours.
So, when I specify that I only want to see the idle_time sums of ONE particular day, the sum is also counting the idle time past 24 hours.
I want to provide the option of CUTTING OFF at that 24 hours. Is this possible?
Here is the query:
{code}
SELECT r.`name` 'Producer'
, m.`name` 'Manufacturer'
-- , timediff(re.time_end, re.time_start) 'Idle Time Length'
, SEC_TO_TIME(SUM((TIME_TO_SEC(TIMEDIFF(re.time_end, re.time_start))))) 'Total Time'
, (SUM((TIME_TO_SEC(TIMEDIFF(re.time_end, re.time_start)))))/3600 'Total Time in Hours'
, (((SUM((TIME_TO_SEC(TIMEDIFF(re.time_end, re.time_start)))))/3600))/((IF(r.resource_status_id = 2, COUNT(r.resource_id), NULL))*24) 'Percent Machine is Idle divided by Machine Hours'
FROM resource_event re
JOIN resource_event_type ret
ON re.resource_event_type_id = ret.resource_event_type_id
JOIN resource_event_type reep
ON ret.parent_resource_event_type_id = reep.resource_event_type_id
JOIN resource r
ON r.`resource_id` = re.`resource_id`
JOIN manufacturer m
ON m.`manufacturer_id` = r.`manufacturer_id`
WHERE re.`resource_event_type_id` = 19
AND ret.`parent_resource_event_type_id` = 3
AND DATE_FORMAT(re.time_start, '%Y-%m-%d') >= '2013-08-12'
AND DATE_FORMAT(re.time_start, '%Y-%m-%d') <= '2013-08-18'
-- AND re.`resource_id` = 8
AND "Idle Time Length" IS NOT NULL
AND r.manufacturer_id = 13
AND r.resource_status_id = 2
GROUP BY 1, 2
Feel free to ignore the dash marks up top. And please tell me if I can be more specific as to figure this out easier and provide less headaches for those willing to help me out.
Thank you so much!

You'll want a conditional SUM, using CASE.
Not sure of syntax for your db exactly, but something like:
, SUM (CASE WHEN TIME_TO_SEC(TIMEDIFF(re.time_end, re.time_start))/3600 > 24 THEN 0
ELSE TIME_TO_SEC(TIMEDIFF(re.time_end, re.time_start))/3600
END)'Total Time in Hours'

This is not an attempt to answer your question. It's being presented as an answer rather than a comment for better formatting and readability.
You have this
AND DATE_FORMAT(re.time_start, '%Y-%m-%d') >= '2013-08-12'
AND DATE_FORMAT(re.time_start, '%Y-%m-%d') <= '2013-08-18'
in your where clause. Using functions like this make your query take longer to execute, especially on indexed fields. Something like this would run quicker.
AND re.time_start >= a date value goes here
AND re.time_start <= another date value goes here

Do you want to cut off when start/end are before/after your time range?
You can use a case to adjust it based on your timeframe, e.g. for time_start
case
when re.time_start < timestamp '2013-08-12 00:00:00'
then timestamp '2013-08-12 00:00:00'
else re.time_start
end
similar for time_end and then use those CASEs within your TIMEDIFF.
Btw, your where-condition for a given date range should be:
where time_start < timestamp '2013-08-19 00:00:00'
and time_end >= timestamp '2013-08-12 00:00:00'
This will return all idle times between 2013-08-12 and 2013-08-18

Change select to a previous date

I have basic knowledge of SQL and have a question:
I am trying to select data from a time series (date and windspeed). I want to select the original wind speed value if it lies between hours 7 and 21. If the hour is outside this range I would like to assign the wind speed to the previous wind speed at hour 21. There is also a concern that there is the occasional point where hour 21 does not exist and would like to assign the windspeed as hour 20... 19 etc until it finds the next available hour.
SELECT
date,
CASE WHEN DATEPART(HH,date) < 7 OR DATEPART(HH,date) > 21
THEN '<WIND SPEED AT HOUR 21> ELSE <WIND SPEED> END AS ModifiedWindspeed
,WindSpeed, winddirection
from TerrainCorrectedHourlyWind w
This might make things clearer. If the hour is in the specified range, select windspeed. If not then select the wind speed from the prior day at 21 hours.

Though you've tagged the question mysql, I'm guessing this is actually SQL Server because of the DATEPART() function used. Try the following, which uses an OUTER APPLY to get your alternate value:
SELECT Date
, CASE
WHEN DATEPART(HOUR, Date)BETWEEN 7 AND 21 THEN w.WindSpeed
ELSE m.WindSpeed
END AS ModifiedWindSpeed
, w.WindSpeed
, w.WindDirection
FROM TerrainCorrectedHourlyWind AS w
OUTER APPLY(SELECT TOP 1 WindSpeed
FROM TerrainCorrectedHourlyWind
WHERE DATEPART(HOUR, Date)BETWEEN 7 AND 21
AND Date < w.Date
ORDER BY Date DESC)AS m;
Just to explain what this is doing--the OUTER APPLY will get the single most recent record (TOP 1 and ORDER BY Date DESC) for dates prior to the record in question (Date < w.Date) as well as within the hours specified. The CASE near the top chooses whether to use the current value or this alternate one based on the hour.

Calculating working days including holidays between dates without a calendar table in oracle SQL

Okay, so I've done quite a lot of reading on the possibility of emulating the networkdays function of excel in sql, and have come to the conclusion that by far the easiest solution is to have a calendar table which will flag working days or non working days. However, due to circumstances out of my control, we don't have access to such a luxury and it's unlikely that we will any time in the near future.
Currently I have managed to bodge together what is undoubtedly a horrible ineffecient query in SQL that does work - the catch is, it will only work for a single client record at a time.
SELECT O_ASSESSMENTS.ASM_ID,
O_ASSESSMENTS.ASM_START_DATE,
O_ASSESSMENTS.ASM_END_DATE,
sum(CASE
When TO_CHAR(O_ASSESSMENTS.ASM_START_DATE + rownum -1,'Day')
= 'Sunday ' THEN 0
When TO_CHAR(O_ASSESSMENTS.ASM_START_DATE + rownum -1,'Day')
= 'Saturday ' THEN 0
WHEN O_ASSESSMENTS.ASM_START_DATE + rownum - 1
IN ('03-01-2000','21-04-2000','24-04-2000','01-05-2000','29-05-2000','28-08-2000','25-12-2000','26-12-2000','01-01-2001','13-04-2001','16-04-2001','07-05-2001','28-05-2001','27-08-2001','25-12-2001','26-12-2001','01-01-2002','29-03-2002','01-04-2002','06-04-2002','03-06-2002','04-06-2002','26-08-2002','25-12-2002','26-12-2002','01-01-2003','18-04-2003','21-04-2003','05-05-2003','26-05-2003','25-08-2003','25-12-2003','26-12-2003','01-01-2004','09-04-2004','12-04-2004','03-05-2004','31-05-2004','30-08-2004','25-12-2004','26-12-2004','27-12-2004','28-12-2004','01-01-2005','03-01-2005','25-03-2005','28-03-2005','02-05-2005','30-05-2005','29-08-2005','27-12-2005','28-12-2005','02-01-2006','14-04-2006','17-04-2006','01-05-2006','29-05-2006','28-08-2006','25-12-2006','26-12-2006','02-01-2007','06-04-2007','09-04-2007','07-05-2007','28-05-2007','27-08-2007','25-12-2007','26-12-2007','01-01-2008','21-03-2008','24-03-2008','05-05-2008','26-05-2008','25-08-2008','25-12-2008','26-12-2008','01-01-2009','10-04-2009','13-04-2009','04-05-2009','25-05-2009','31-08-2009','25-12-2009','28-12-2009','01-01-2010','02-04-2010','05-04-2010','03-05-2010','31-05-2010','30-08-2010','24-12-2010','27-12-2010','28-12-2010','31-12-2010','03-01-2011','22-04-2011','25-04-2011','29-04-2011','02-05-2011','30-05-2011','29-08-2011','26-12-2011','27-12-2011')
THEN 0
ELSE 1
END)-1 AS Week_Day
From O_ASSESSMENTS,
ALL_OBJECTS
WHERE O_ASSESSMENTS.ASM_QSA_ID IN ('TYPE1')
AND O_ASSESSMENTS.ASM_END_DATE >= '01/01/2012'
AND O_ASSESSMENTS.ASM_ID = 'A00000'
AND ROWNUM <= O_ASSESSMENTS.ASM_END_DATE-O_ASSESSMENTS.ASM_START_DATE+1
GROUP BY
O_ASSESSMENTS.ASM_ID,
O_ASSESSMENTS.ASM_START_DATE,
O_ASSESSMENTS.ASM_END_DATE
Basically, I'm wondering if a) I should stop wasting my time on this or b) is it possible to get this to work for multiple clients? Any pointers appreciated thanks!
Edit: Further clarification - I already work out timescales using excel, but it would be ideal if we could do it in the report as the report in question is something that we would like end users to be able to run without any further manipulation.
Edit:
MarkBannister's answer works perfectly albeit slowly (though I had expected as much given it's not the preferred solution) - the challenge now lies in me integrating this into an existing report!
with
calendar_cte as (select
to_date('01-01-2000')+level-1 calendar_date,
case when to_char(to_date('01-01-2000')+level-1, 'day') in ('sunday ','saturday ') then 0 when to_date('01-01-2000')+level-1 in ('03-01-2000','21-04-2000','24-04-2000','01-05-2000','29-05-2000','28-08-2000','25-12-2000','26-12-2000','01-01-2001','13-04-2001','16-04-2001','07-05-2001','28-05-2001','27-08-2001','25-12-2001','26-12-2001','01-01-2002','29-03-2002','01-04-2002','06-04-2002','03-06-2002','04-06-2002','26-08-2002','25-12-2002','26-12-2002','01-01-2003','18-04-2003','21-04-2003','05-05-2003','26-05-2003','25-08-2003','25-12-2003','26-12-2003','01-01-2004','09-04-2004','12-04-2004','03-05-2004','31-05-2004','30-08-2004','25-12-2004','26-12-2004','27-12-2004','28-12-2004','01-01-2005','03-01-2005','25-03-2005','28-03-2005','02-05-2005','30-05-2005','29-08-2005','27-12-2005','28-12-2005','02-01-2006','14-04-2006','17-04-2006','01-05-2006','29-05-2006','28-08-2006','25-12-2006','26-12-2006','02-01-2007','06-04-2007','09-04-2007','07-05-2007','28-05-2007','27-08-2007','25-12-2007','26-12-2007','01-01-2008','21-03-2008','24-03-2008','05-05-2008','26-05-2008','25-08-2008','25-12-2008','26-12-2008','01-01-2009','10-04-2009','13-04-2009','04-05-2009','25-05-2009','31-08-2009','25-12-2009','28-12-2009','01-01-2010','02-04-2010','05-04-2010','03-05-2010','31-05-2010','30-08-2010','24-12-2010','27-12-2010','28-12-2010','31-12-2010','03-01-2011','22-04-2011','25-04-2011','29-04-2011','02-05-2011','30-05-2011','29-08-2011','26-12-2011','27-12-2011','01-01-2012','02-01-2012') then 0 else 1 end working_day
from dual
connect by level <= 1825 + sysdate - to_date('01-01-2000') )
SELECT
a.ASM_ID,
a.ASM_START_DATE,
a.ASM_END_DATE,
sum(c.working_day)-1 AS Week_Day
From
O_ASSESSMENTS a
join calendar_cte c
on c.calendar_date between a.ASM_START_DATE and a.ASM_END_DATE
WHERE a.ASM_QSA_ID IN ('TYPE1')
and a.ASM_END_DATE >= '01/01/2012'
GROUP BY
a.ASM_ID,
a.ASM_START_DATE,
a.ASM_END_DATE

There are a few ways to do this. Perhaps the simplest might be to create a CTE that produces a virtual calendar table, based on Oracle's connect by syntax, and then join it to the Assesments table, like so:
with calendar_cte as (
select to_date('01-01-2000')+level-1 calendar_date,
case when to_char(to_date('01-01-2000')+level-1, 'Day')
in ('Sunday ','Saturday ') then 0
when to_date('01-01-2000')+level-1
in ('03-01-2000','21-04-2000','24-04-2000','01-05-2000','29-05-2000','28-08-2000','25-12-2000','26-12-2000','01-01-2001','13-04-2001','16-04-2001','07-05-2001','28-05-2001','27-08-2001','25-12-2001','26-12-2001','01-01-2002','29-03-2002','01-04-2002','06-04-2002','03-06-2002','04-06-2002','26-08-2002','25-12-2002','26-12-2002','01-01-2003','18-04-2003','21-04-2003','05-05-2003','26-05-2003','25-08-2003','25-12-2003','26-12-2003','01-01-2004','09-04-2004','12-04-2004','03-05-2004','31-05-2004','30-08-2004','25-12-2004','26-12-2004','27-12-2004','28-12-2004','01-01-2005','03-01-2005','25-03-2005','28-03-2005','02-05-2005','30-05-2005','29-08-2005','27-12-2005','28-12-2005','02-01-2006','14-04-2006','17-04-2006','01-05-2006','29-05-2006','28-08-2006','25-12-2006','26-12-2006','02-01-2007','06-04-2007','09-04-2007','07-05-2007','28-05-2007','27-08-2007','25-12-2007','26-12-2007','01-01-2008','21-03-2008','24-03-2008','05-05-2008','26-05-2008','25-08-2008','25-12-2008','26-12-2008','01-01-2009','10-04-2009','13-04-2009','04-05-2009','25-05-2009','31-08-2009','25-12-2009','28-12-2009','01-01-2010','02-04-2010','05-04-2010','03-05-2010','31-05-2010','30-08-2010','24-12-2010','27-12-2010','28-12-2010','31-12-2010','03-01-2011','22-04-2011','25-04-2011','29-04-2011','02-05-2011','30-05-2011','29-08-2011','26-12-2011','27-12-2011')
then 0
else 1
end working_day
from dual
connect by level <= 36525 + sysdate - to_date('01-01-2000') )
SELECT a.ASM_ID,
a.ASM_START_DATE,
a.ASM_END_DATE,
sum(c.working_day) AS Week_Day
From O_ASSESSMENTS a
join calendar_cte c
on c.calendar_date between a.ASM_START_DATE and a.ASM_END_DATE
WHERE a.ASM_QSA_ID IN ('TYPE1') and
a.ASM_END_DATE >= '01/01/2012' -- and a.ASM_ID = 'A00000'
GROUP BY
a.ASM_ID,
a.ASM_START_DATE,
a.ASM_END_DATE
This will produce a virtual table populated with dates from 01 January 2000 to 10 years after the current date, with all weekends marked as non-working days and all days specified in the second in clause (ie. up to 27 December 2011) also marked as non-working days.
The drawback of this method (or any method where the holiday dates are hardcoded into the query) is that each time new holiday dates are defined, every single query that uses this approach will have to have those dates added.

If you can't use a calendar table in Oracle, you might be better off exporting to Excel. Brute force always works.
Networkdays() "returns the number of whole working days between start_date and end_date. Working days exclude weekends and any dates identified in holidays."
Excluding weekends seems fairly straightforward. Every 7-day period will contain two weekend days. You'll just need to take some care with the leftover days.
Holidays are a different story. You have to either store them or pass them as an argument. If you could store them, you'd store them in a calendar table, and your problem would be over. But you can't do that.
So you're looking at passing them as an argument. Off the top of my head--and I haven't had any tea yet this morning--I'd consider a common table expression or a wrapper for a stored procedure.