I have an Access table (Logs) like this:
pk
modID
relID
DateTime
TxType
1
1234
22.3
10/1/22 04:00
1
2
1234
23.1
10/10/22 06:00
1
3
1234
23.1
10/11/22 07:00
2
4
1234
23.1
10/12/22 08:00
3
5
4321
22.3
10/2/22 06:00
7
6
4321
23.1
10/10/22 06:00
1
7
4321
23.1
10/11/22 07:30
3
Trying to write a query as part of a function that searches this table:
for all records matching a given modID and relID (e.g. 1234 and 23.1),
picks the most recent one (the MAX of DateTime),
returns the TxType for that record.
However, a bit new to Access and its query structure is vexing me. I landed on this but because I have to include a Total/Aggregate function for TxType I had to either choose Group By (not what I want) or Last (closer, but returns junk results). The SQL for my query is currently:
SELECT Last(Logs.TxType) AS LastOfTxType, Max(Logs.DateTime) AS MaxOfDateTime
FROM Logs
GROUP BY Logs.dmID, Logs.relID
HAVING (((Logs.dmID)=[EnterdmID]) AND ((Logs.relID)=[EnterrelID]));
It returns the TxType field when I pass it the right parameters, but not the correct record - I would like to be rid of the Last() bit but if I remove it Access complains that I don't have it as part of an aggregate function.
Anyone that can point me in the right direction here?
Have you tried
SELECT TOP 1 TxtType
FROM Logs
WHERE (((Logs.dmID)=[EnterdmID]) AND ((Logs.relID)=[EnterrelID]))
ORDER BY DateTime DESC;
That will give you the latest single data row based on your DateTime field and other criteria.
It would be awesome if there was a way to index rows during a query.
Is there a way to SELECT (compute) the difference of a single column between consecutive rows?
Let's say, something like the following query
SELECT
toStartOfDay(stamp) AS day,
count(day ) AS events ,
day[current] - day[previous] AS difference, -- how do I calculate this
day[current] / day[previous] as percent, -- and this
FROM records
GROUP BY day
ORDER BY day
I want to get the integer and percentage difference between the current row's 'events' column and the previous one for something similar to this:
day
events
difference
percent
2022-01-06 00:00:00
197
NULL
NULL
2022-01-07 00:00:00
656
459
3.32
2022-01-08 00:00:00
15
-641
0.02
2022-01-09 00:00:00
7
-8
0.46
2022-01-10 00:00:00
137
130
19.5
My version of Clickhouse doesn't support window-function but, on looking about the LAG() function mentioned in the comments, I found neighbor(), which works perfectly for what I'm trying to do
SELECT
toStartOfDay(stamp) AS day,
count(day ) AS events ,
(events - neighbor(events, -1)) as diff,
(events / neighbor(events, -1)) as perc
FROM records
GROUP BY day
ORDER BY day
seconfHere is an example:
ID Datetime1 datetime2 (Results needed)
1 1/1/2010 7:54 1/2/2010 6:54 23
1 1/1/2010 7:54 1/4/2010 6:54 48
1 1/1/2010 7:54 1/5/2010 6:54 24
2 1/5/2010 11:00 1/8/2010 11:00 72
3 1/30/2010 23:05 2/1/2010 22:05 47
notice ID 1 in the first row it did a normal datediff but in the second and third row I need it to use the startdate of datetime2 and enddate of datetime2 of thee same ID.
turnaround time column is what is the output column I need, I only tried normal datediff but it just calculates the difference between datetime1 and datetime2. my problem is that it can be many IDs with a value of 1, so I need the datediff to dynamically update the startdate if another enddate exist for the same ID.
Im' working in a RDBMS 'Microsoft SQL server'
the code i tried is as followed:
select
*
,datediff(hh,datetime1,datetime2) as 'Turnaround time'
from
my_table
order by datetime1 asc
i hope this clears it out a little bit.
thank you in advance
the answer was Lead and Lag functions URL below:
https://www.databasejournal.com/features/mssql/lead-and-lag-functions-in-sql-server-2012.html
I have a table containing a large amount of data which is stored on change.
tbl_bigOne
----------
timestamp | var01 | var02 | ...
2016-01-14 15:20:21 | 10.1 | 100.6 | ...
2016-01-14 15:20:26 | 11.2 | 110.3 | ...`
2016-01-14 15:21:27 | 52.1 | 620.1 | ...
2016-01-14 15:35:00 | 13.5 | 230.6 | ...
...
2016-01-15 09:18:01 | 94.4 | 140.0 | ...
2016-01-15 10:01:15 | 105.3 | 188.7 | ...
...
and so on for years of data
What I would like to obtain is a query/stored procedure that given two datetime references (date_from and date_to) gives the required selected data.
Now, the query just mentioned is pretty straight forward what I would also like to achieve is to set the maximum number of rows returned per day (if data is available) while doing the average of the values.
Let's give a few examples:
date_from: 2016-01-14 00:00:00
date_to: 2016-01-20 23:59:59
max_points:12
in this case the time windows is of 7 days and in this one i would like to have a maximum of 12 rows for each days of the 7 day window, giving a max total of 84 rows whilst doing the average from all the grouping done since, the data for each day is now partitioned by 12.
It is possible to see this partitioning as if every hour worth of data for that specific day is averaged, generating one row of the 12 required for a day.
date_from: 2016-01-14 00:00:00
date_to: 2016-01-14 23:59:59
max_points:1440
in this case the time window is one day worth and, if available, i would like to have a maximum of 1440 rows (for each day) for the selected period.
In this way the parameter defines the maximum number of rows for each day. The minimum time window is one day nothing below that.
Can something like this be achieved just using TSQL?
Thank you.
edit for taking care of the observations raised by #Thorsten Kettner
Use the analytic function ROW_NUMBER() to number the matching rows per day. Then only keep rows up to the given limit. If you want the rows arbitrarily chosen when there exist more than needed, then number the rows in random order using NEWID().
select timestmp, var01, var02, var03
from
(
select
mytable.*,
row_number() over (partition by convert(date, timestmp) order by newid()) as rn
from mytable
where convert(date, timestmp) between #start_date and #end_date
) numbered
where rn <= #limit
order by timestmp;
I have a table where our product records its activity log. The product starts working at 23:00 every day and usually works one or two hours. This means that once a batch started at 23:00, it finishes about 1:00am next day.
Now, I need to take statistics on how many posts are registered per batch but cannot figure out a script that would allow me achiving this. So far I have following SQL code:
SELECT COUNT(*), DATEPART(DAY,registrationtime),DATEPART(HOUR,registrationtime)
FROM RegistrationMessageLogEntry
WHERE registrationtime > '2014-09-01 20:00'
GROUP BY DATEPART(DAY, registrationtime), DATEPART(HOUR,registrationtime)
ORDER BY DATEPART(DAY, registrationtime), DATEPART(HOUR,registrationtime)
which results in following
count day hour
....
1189 9 23
8611 10 0
2754 10 23
6462 11 0
1885 11 23
I.e. I want the number for 9th 23:00 grouped with the number for 10th 00:00, 10th 23:00 with 11th 00:00 and so on. How could I do it?
You can do it very easily. Use DATEADD to add an hour to the original registrationtime. If you do so, all the registrationtimes will be moved to the same day, and you can simply group by the day part.
You could also do it in a more complicated way using CASE WHEN, but it's overkill on the view of this easy solution.
I had to do something similar a few days ago. I had fixed timespans for work shifts to group by where one of them could start on one day at 10pm and end the next morning at 6am.
What I did was:
Define a "shift date", which was simply the day with zero timestamp when the shift started for every entry in the table. I was able to do so by checking whether the timestamp of the entry was between 0am and 6am. In that case I took only the date of this DATEADD(dd, -1, entryDate), which returned the previous day for all entries between 0am and 6am.
I also added an ID for the shift. 0 for the first one (6am to 2pm), 1 for the second one (2pm to 10pm) and 3 for the last one (10pm to 6am).
I was then able to group over the shift date and shift IDs.
Example:
Consider the following source entries:
Timestamp SomeData
=============================
2014-09-01 06:01:00 5
2014-09-01 14:01:00 6
2014-09-02 02:00:00 7
Step one extended the table as follows:
Timestamp SomeData ShiftDay
====================================================
2014-09-01 06:01:00 5 2014-09-01 00:00:00
2014-09-01 14:01:00 6 2014-09-01 00:00:00
2014-09-02 02:00:00 7 2014-09-01 00:00:00
Step two extended the table as follows:
Timestamp SomeData ShiftDay ShiftID
==============================================================
2014-09-01 06:01:00 5 2014-09-01 00:00:00 0
2014-09-01 14:01:00 6 2014-09-01 00:00:00 1
2014-09-02 02:00:00 7 2014-09-01 00:00:00 2
If you add one hour to registrationtime, you will be able to group by the date part:
GROUP BY
CAST(DATEADD(HOUR, 1, registrationtime) AS date)
If the starting hour must be reflected accurately in the output (as 9, 23, 10, 23 rather than as 10, 0, 11, 0), you could obtain it as MIN(registrationtime) in the SELECT clause:
SELECT
count = COUNT(*),
day = DATEPART(DAY, MIN(registrationtime)),
hour = DATEPART(HOUR, MIN(registrationtime))
Finally, in case you are not aware, you can reference columns by their aliases in ORDER BY:
ORDER BY
day,
hour
just so that you do not have to repeat the expressions.
The below query will give you what you are expecting..
;WITH CTE AS
(
SELECT COUNT(*) Count, DATEPART(DAY,registrationtime) Day,DATEPART(HOUR,registrationtime) Hour,
RANK() over (partition by DATEPART(HOUR,registrationtime) order by DATEPART(DAY,registrationtime),DATEPART(HOUR,registrationtime)) Batch_ID
FROM RegistrationMessageLogEntry
WHERE registrationtime > '2014-09-01 20:00'
GROUP BY DATEPART(DAY, registrationtime), DATEPART(HOUR,registrationtime)
)
SELECT SUM(COUNT) Count,Batch_ID
FROM CTE
GROUP BY Batch_ID
ORDER BY Batch_ID
You can write a CASE statement as below
CASE WHEN DATEPART(HOUR,registrationtime) = 23
THEN DATEPART(DAY,registrationtime)+1
END,
CASE WHEN DATEPART(HOUR,registrationtime) = 23
THEN 0
END