SQL to find timespan between rows based on ID - sql

Question

I have the following table in a SQL db (HeartbeatHistory)
Timestamp | Comment | Id
------------------------
The comment can contain OK or ERR
The Id is the Id of the thing that has that comment.
I want to be able to query the table and find the durations that any given id was in an Error state.
Timestamp | Comment | Id
------------------------
12:00:00 | OK | 1
11:59:00 | ERR | 2
11:58:00 | OK | 4
11:57:00 | OK | 3
11:45:00 | ERR | 4
11:20:00 | OK | 2
11:00:00 | ERR | 3
11:30:00 | OK | 5
11:20:00 | ERR | 1
11:10:00 | OK | 1
11:00:00 | ERR | 1
10:30:00 | ERR | 5
So in the above table If I queried for 11:00:00 to 13:00:00 I would want to see.
ErrorStart | ErrorEnd | Id
--------------------------
11:00:00 | 11:10:00 | 1
11:20:00 | 12:00:00 | 1
11:59:00 | 12:00:00 | 2
11:00:00 | 11:57:00 | 3
11:45:00 | 11:58:00 | 4
11:00:00 | 11:30:00 | 5
(notice 5 started error before query date!!)
Is this possible? Also an Id might change state multiple times during the queried period.
So far I have this, which works for a single Id, but I need to make it work for multiple Ids.
declare #startDate datetime = #from;
declare #endDate datetime = #to;
declare #kpiId = 1;
select Foo.RowCreatedTimestamp, Foo.Comment, Foo.NextTimeStamp, Foo.NextComment, Foo.HeartBeatId, Foo.NextHeartBeatId
from (
select RowCreatedTimestamp, Comment,
lag(RowCreatedTimestamp, 1, 0) over (order by RowCreatedTimestamp desc) as NextTimeStamp,
lag(Comment, 1, 0) over (order by RowCreatedTimestamp desc) as NextComment,
HeartBeatId
from dbo.tblHeartbeatHistory
where RowCreatedTimestamp >= #startDate and RowCreatedTimestamp <= #endDate
and HeartbeatId in
(
select HeartbeatId
from dbo.tblKpiHeartBeats
where KpiId = #kpiId
)
) as Foo
where Foo.Comment like '%set to ERR%'
order by Foo.RowCreatedTimestamp desc;
So if the select HeartbeatId from dbo.tblKpiHeartBeats returns a single Id, this works. As soon as their are multiple id's it does not :(
To avoid confusion:
The table with the Timestamp, Comment and Id is HeartbeatHistory.
The other table referenced in my SQL is dbo.tblKpiHeartBeats.
This table looks like:
Kpi | HeartbeatId
-----------------
1 | 1
1 | 2
1 | 3
1 | 4
1 | 5
So i want all the error intervals for Kpi = 1, it would return the error intervals for HeartbeatId 1,2,3,4 and 5.
Further note. The data may have multiple errors in a row before an OK comes in.
It may just be all ERR for the query period or all OK.

Answer 1

You can add second CTE Id you want full join ERR AND OK rows (Code below only for OK rows)
WIRH History AS (
SELECT
FROM HeartbeatHistory
WHERE Timestamp BETWEEN #DateStart AND #DateEnd
), Errors AS(
SELECT Id, MIN(Timestamp) AS ErrorStart
FROM History
WHERE Comment = 'ERR'
GROUP BY Id
)
SELECT
ErrorStart = E.ErrorStart ,
ErrorEnd = O.Timestamp,
Id = O.Id
FROM History O
LEFT JOIN Errors E ON E.Id = O.Id
WHERE O.Comment = 'OK'
Edit: You can add prevOK timespan (or PK) column to the table (probably computed persistent) - link to last good row. It will be used as Id of row in your report.
Try this index:
CREATE INDEX IDX_EXAMPLE ON HeartbeatHistory (Timestamp, Id, prevOK, Comment)
WIRH History AS (
SELECT
FROM HeartbeatHistory
WHERE Timestamp BETWEEN #DateStart AND #DateEnd
)
SELECT
ErrorStart = E.ErrorStart ,
ErrorEnd = O.Timestamp,
Id = O.Id
FROM History O
OUTER APPLY (
SELECT MIN(Timestamp) AS ErrorStart
FROM History E
WHERE E.Id = O.ID AND E.prevOK = O.prevOK
)
WHERE O.Comment = 'OK'

Answer 2

The simplest method is to use lead(). If I assume that ERR does not occur twice in a row (as in your sample data):
select (case when timestamp >= '11:00:00' then timestamp else '11:00:00' end) as errorStart,
(case when next_timestamp <= '13:00:00' then next_timestamp else '13:00:00') as errorEnd,
id
from (select t.*,
lead(timestamp) over (partition by id order by timestamp) as next_timestamp
from t
) t
where comment = 'ERR' and
(timestamp <= '13:00:00' and
(next_timestamp >= '11:00:00' or next_timestamp is null)
);

Answer 3

Try this:
DECLARE #table TABLE (Timestmp TIME(1), Comment NVARCHAR(5), Id INT) --your table
INSERT INTO #table VALUES
('12:00:00','OK ','1'),('11:59:00','ERR','2'),('11:58:00','OK ','4'),('11:57:00','OK ','3'),
('11:45:00','ERR','4'),('11:20:00','OK ','2'),('11:00:00','ERR','3'),('11:30:00','OK ','5'),
('11:20:00','ERR','1'),('11:10:00','OK ','1'),('11:00:00','ERR','1'),('10:30:00','ERR','5')
DECLARE #ROWER TABLE (id INT IDENTITY(1,1), Timestmp TIME(1))
INSERT INTO #ROWER SELECT Timestmp FROM #table WHERE Comment='OK' ORDER BY Timestmp
DECLARE #TIME TIME(1) = '11:00:00' --your condition
SELECT DISTINCT CASE WHEN A.Timestmp >=#TIME THEN A.Timestmp ELSE #TIME END ErrorStart,
CASE WHEN B.Timestmp > A.Timestmp THEN B.Timestmp ELSE '' END ErrorEnd,
A.Id FROM (
SELECT ROW_NUMBER() OVER (ORDER BY id,Timestmp) rowid,* FROM #table WHERE Comment = 'ERR'
) A LEFT JOIN (
SELECT ROW_NUMBER() OVER (ORDER BY id,Timestmp) rowid,* FROM #table WHERE Comment = 'OK'
) B ON A.rowid = B.rowid
LEFT JOIN ( SELECT A.id,A.Timestmp t1,B.Timestmp t2 FROM #ROWER A
LEFT JOIN (SELECT id-1 id, Timestmp FROM #ROWER) B ON A.id=B.id
) C ON A.Timestmp BETWEEN C.t1 AND C.t2 ORDER BY A.Id
Hope it helps. :)