I have get difference between the current Issue Reset and next stop time in Postgres SQL. I am not able to understand, how can i get this done using window functions. I tried NEXT_VALUE and FIRST_VALUE, but i am seeing examples for moving aggregates. I need a single query to get this.
I need to achieve difference between '22/08/2020 11:29:00' and '17/08/2020 11:19:00' which tells me duration of running time.
It looks like you want the difference between each stoptime and the latest prior issue. If issues and stop times are properly interleaved, as you explained in the comments, then you can use window functions as follows:
select t.*, stop_time - max_issue as diff
from (
select t.*, max(issue) over(order by issue) max_issue
from mytable t
) t
where stop_time is not null
Related
I have a table as shown below.
time
Event
2021-03-19T17:15:05
A
2021-03-19T17:15:11
B
2021-03-19T17:15:11
C
2021-03-19T17:15:12
A
2021-03-19T17:15:14
C
I want to find the average time between event A and the event following it.
How do I find it using an SQL query?
here desired output is: 4 seconds.
I really appreciate any help you can provide.
The basic idea is lead() to get the time from the next row. Then you need to calculate the difference. So for all rows:
select t.*,
(to_unix_timestamp(lead(time) over (order by time) -
to_unix_timestamp(time)
) as diff_seconds
from t;
Use a subquery and filtering for just A and the average:
select avg(diff_seconds)
from (select t.*,
(to_unix_timestamp(lead(time) over (order by time) -
to_unix_timestamp(time)
) as diff_seconds
from t
) t
where event = 'A';
is there a way in SQL to find a previous value, not necessarily in the previous row, within the same SELECT statement?
See picture below. I'd like to add another column, ELAPSED, that calculates the time difference between TIMERSTART, but only when DEVICEID is the same, and I_TYPE is viewDisplayed. e.g. subtract 1 from 2, store difference in 3, store 0 in 4 because i_type is not viewDisplayed, subtract 2 from 5, store difference in 6, and so on.
It has to be a statement, I can't use a stored procedure in this case.
SELECT DEVICEID, I_TYPE, TIMERSTART,
O AS ELAPSED -- CASE WHEN <CONDITION> THEN TIMEDIFF() ELSE 0 END AS ELAPSED
FROM CLIENT_USAGE
ORDER BY TIMERSTART ASC
I'm using SAP HANA DB, but it works pretty much like the latest version of MS-SQL. So, if you know how to make it work in SQL, I can make it work in HANA.
You can make a subquery to find the last time entered previous to the row in question.
select deviceid, i_type, timerstart, (timerstart - timerlast) as elapsed.
from CLIENT_USAGE CU
join ( select top 1 timerstart as timerlast
from CLIENT_USAGE C
where (C.i_type = CU.i_type) and
(C.deviceid = CU.deviceid) and (C.timerstart < CU.timerstart)
order by C.timerstart desc
) as temp1
on temp1.i_type = CU.i_type
order by timerstart asc
This is a rough sketch of what the sql should look like I do not know what your primary key is on this table if it is i_type or i_type and deviceid. But this should help with how to atleast calculate the field. I do not think it would be necessary to store the value unless this table is very large or the hardware being used is very slow. It can be calculated rather easily each time this query is run.
SAP HANA supports window functions:
select DEVICEID,
TIMERSTART,
lag(TIMERSTART) over (partition by DEVICEID order by TIMERSTART) as previous_start
from CLIENT_USAGE
Then you can wrap this in parentheses and manipulate the data to your hearts' content
I am trying to count each item in a database table, that is deployments. I have counted the total number of items 3879, by doing this:
use Bamboo_Version6
go
SELECT Count(STARTED_DATE)
FROM [Bamboo_Version6].[dbo].[DEPLOYMENT_RESULT]
But I have been struggling to get the number of items each day until the start. I have tried using some of the other similar answers to this like:
select STARTED_Date, count(deploymentID)
from [Bamboo_Version6].[dbo].[DEPLOYMENT_RESULT]
WHERE STARTED_Date>=dateadd(day,datediff(day,0,STARTED_Date)- 7,0)
GROUP BY STARTED_Date
But this will return every id, and a 1 beside it because the dates have times which are making it unique, so I tried doing this: CONVERT(varchar(12),STARTED_DATE,110) to try and fix the problem but it still happens. How can I count this without, getting all the id's or every id as 1 each time?
Remove the time component:
select cast(STARTED_Date as date) as dte, count(deploymentID)
from [Bamboo_Version6].[dbo].[DEPLOYMENT_RESULT]
group by cast(STARTED_Date as date)
order by dte;
I'm not sure what the WHERE clause is supposed to be doing, so I just removed it. If it is useful, add it back in.
I have another efficient way of doing this, may be try this with an over clause
SELECT cast(STARTED_DATE AS DATE) AS Deployment_date,
COUNT(deploymentID) OVER ( PARTITION BY cast(STARTED_DATE AS DATE) ORDER BY STARTED_DATE) AS NumberofDeployments
FROM [Bamboo_Version6].[dbo].[DEPLOYMENT_RESULT]
For this SQL,
SELECT CID, Time, Val
FROM MyTable
WHERE CID = 8
I get the following data,
CID, Time, Val
8,2016-10-19 13:49:06.217,7.036
8,2016-10-19 13:49:15.237,6.547
8,2016-10-19 13:49:46.063,6.292
8,2016-10-19 13:49:57.387,5.998
I want each of Time value minus the starting time, which can be calculated by
SELECT MIN(Time) StartTime
FROM MyTable
WHERE CID = 8
I know that I can define a T-SQL variable to do that, However, is it possible to do the task, getting the relative time instead of absolute time for each record, in one SQL?
You can use min() window function to get the minimum time for each id and use it for subtraction.
select cid,time,val,
datediff(millisecond,min(time) over(partition by cid),time) as diff
from mytable
Change the difference interval (millisecond shown) per your requirement. There can be an overflow if the difference is too big.
Here's an example of what I'm looking for:
I have data that comes in as a lifetime total in gallons. I want to be able to display the data as a running total over the time period I am selecting for rather than as a lifetime total. For example:
timestamp lifetimeTotal runningTotal
1:30 3000 0
1:31 3001 1
1:32 3005 5
1:33 3010 10
I'm not sure how to go about doing this. I was looking at examples like this one using over but it's not quite what I'm looking for: I don't want to add the rows together every time, rather I want to add the difference between the two rows. Right now I am simply selecting the lifetime totals and displaying that.
Any ideas? I will add code if necessary but there's not much to show besides my select statement; I am having trouble thinking of a way to do this conceptually.
This should give difference between the current lifetimeTotal and the min lifetimeTotal
SELECT timestamp,
lifetimeTotal,
lifetimeTotal - MIN(lifetimeTotal) OVER () as runningTotal
FROM Table
This can be easily done using window functions:
SELECT [timestamp], lifetimeTotal,
COALESCE(SUM(diff) OVER (ORDER BY [timestamp]), 0) AS runningTotal
FROM (
SELECT [timestamp],
lifetimeTotal,
lifetimeTotal - LAG(lifetimeTotal) OVER (ORDER BY [timestamp]) AS diff
FROM mytable ) t
The above query uses LAG to calculate the difference between current and previous row. SUM OVER is then used in an outer query to calculate the running total of the difference.
Demo here