I have a table that stores time, heart_rate, and player_id. I need to somehow take an average of the heart rate data over the last five minutes and group each average by the player ID.
Another option is to use DATEDIFF
SELECT AVG(heart_rate) AS heart_rate,
player_id
FROM tablename
WHERE DATEDIFF(MINUTE, time, GETDATE()) < 5
GROUP BY player_id
This is partly a response to Donal's answer (and too long for a comment).
You do not want to use the following:
WHERE datepart(minute, (time - GETDATE())) < 5
There are two reasons. First, this cannot make use of an index on time. That is, the calculation is not sargable. Second, the subtraction is backwards, unless time values are in the future.
A better way to write this is:
select player_id, avg(heart_rate)
from table t
where time >= dateadd(minute, -5, getdate())
group by player_id;
Related
I have a table that acts as a message log, with the two key tables being TIMESTAMP and TEXT. I'm working on a query that grabs all alerts (from TEXT) for the past 30 days (based on TIMESTAMP) and gives a daily average for those alerts.
Here is the query so far:
--goback 30 days start at midnight
declare #olderdate as datetime
set #olderdate = DATEADD(Day, -30, DATEDIFF(Day, 0, GetDate()))
--today at 11:59pm
declare #today as datetime
set #today = dateadd(ms, -3, (dateadd(day, +1, convert(varchar, GETDATE(), 101))))
print #today
--Grab average alerts per day over 30 days
select
avg(x.Alerts * 1.0 / 30)
from
(select count(*) as Alerts
from MESSAGE_LOG
where text like 'The process%'
and text like '%has alerted%'
and TIMESTAMP between #olderdate and #today) X
However, I want to add something that checks whether there were any alerts for a day and, if there are no alerts for that day, doesn't include it in the average. For example, if there are 90 alerts for a month but they're all in one day, I wouldn't want the average to be 3 alerts per day since that's clearly misleading.
Is there a way I can incorporate this into my query? I've searched for other solutions to this but haven't been able to get any to work.
This isn't written for your query, as I don't have any DDL or sample data, thus I'm going to provide a very simple example instead of how you would do this.
USE Sandbox;
GO
CREATE TABLE dbo.AlertMessage (ID int IDENTITY(1,1),
AlertDate date);
INSERT INTO dbo.AlertMessage (AlertDate)
VALUES('20190101'),('20190101'),('20190105'),('20190110'),('20190115'),('20190115'),('20190115');
GO
--Use a CTE to count per day:
WITH Tots AS (
SELECT AlertDate,
COUNT(ID) AS Alerts
FROM dbo.AlertMessage
GROUP BY AlertDate)
--Now the average
SELECT AVG(Alerts*1.0) AS DayAverage
FROM Tots;
GO
--Clean up
DROP TABLE dbo.AlertMessage;
You're trying to compute a double-aggregate: The average of daily totals.
Without using a CTE, you can try this as well, which is generalized a bit more to work for multiple months.
--get a list of events per day
DECLARE #Event TABLE
(
ID INT NOT NULL IDENTITY(1, 1)
,DateLocalTz DATE NOT NULL--make sure to handle time zones
,YearLocalTz AS DATEPART(YEAR, DateLocalTz) PERSISTED
,MonthLocalTz AS DATEPART(MONTH, DateLocalTz) PERSISTED
)
/*
INSERT INTO #Event(EntryDateLocalTz)
SELECT DISTINCT CONVERT(DATE, TIMESTAMP)--presumed to be in your local time zone because you did not specify
FROM dbo.MESSAGE_LOG
WHERE UPPER([TEXT]) LIKE 'THE PROCESS%' AND UPPER([TEXT]) LIKE '%HAS ALERTED%'--case insenitive
*/
INSERT INTO #Event(DateLocalTz)
VALUES ('2018-12-31'), ('2019-01-01'), ('2019-01-01'), ('2019-01-01'), ('2019-01-12'), ('2019-01-13')
--get average number of alerts per alerting day each month
-- (this will not return months with no alerts,
-- use a LEFT OUTER JOIN against a month list table if you need to include uneventful months)
SELECT
YearLocalTz
,MonthLocalTz
,AvgAlertsOfAlertingDays = AVG(CONVERT(REAL, NumDailyAlerts))
FROM
(
SELECT
YearLocalTz
,MonthLocalTz
,DateLocalTz
,NumDailyAlerts = COUNT(*)
FROM #Event
GROUP BY YearLocalTz, MonthLocalTz, DateLocalTz
) AS X
GROUP BY YearLocalTz, MonthLocalTz
ORDER BY YearLocalTz ASC, MonthLocalTz ASC
Some things to note in my code:
I use PERSISTED columns to get the month and year date parts (because I'm lazy when populating tables)
Use explicit CONVERT to escape integer math that rounds down decimals. Multiplying by 1.0 is a less-readable hack.
Use CONVERT(DATE, ...) to round down to midnight instead of converting back and forth between strings
Do case-insensitive string searching by making everything uppercase (or lowercase, your preference)
Don't subtract 3 milliseconds to get the very last moment before midnight. Change your semantics to interpret the end of a time range as exclusive, instead of dealing with the precision of your datatypes. The only difference is using explicit comparators (i.e. use < instead of <=). Also, DATETIME resolution is 1/300th of a second, not 3 milliseconds.
Avoid using built-in keywords as column names (i.e. "TEXT"). If you do, wrap them in square brackets to avoid ambiguity.
Instead of dividing by 30 to get the average, divide by the count of distinct days in your results.
select
avg(x.Alerts * 1.0 / x.dd)
from
(select count(*) as Alerts, count(distinct CAST([TIMESTAMP] AS date)) AS dd
...
I am running the following query
select DateTime
from Calls
where DateTime > '17 Oct 2018 00:00:00.000' and
DialedNumberID = '1234'
What would this give me is a list of all the times that this number was dialled on the specific date.
Essentially what I am looking for is a query that would give me the average calls that take place every X minutes and would like to run the query for the whole year.
Thanks
I guess you have a table named Calls with the columns DateTime and DialedNumberID.
You can summarize the information in that table year-by-year using the kind of pattern.
SELECT YEAR(`DateTime`),
DialedNumberID,
COUNT(*) call_count
FROM Calls
GROUP BY YEAR(`DateTime`), DialedNumberID
The trick in this pattern is to GROUP BY f(date) . The function f() reduces any date to the year in which it occures.
Summary by five minute intervals, you need f(date) that reduces datestamps to five minute intervals. That function is a good deal more complex than YEAR().
DATE_FORMAT(datestamp,'%Y-%m-%d %H:00') + INTERVAL (MINUTE(datestamp) - MINUTE(datestamp) MOD 5)
Given, for example, 2001-09-11 08:43:00, this gives back 2001-09-11 08:40:00.
So, here's your summary by five minute intervals.
SELECT DATE_FORMAT(`DateTime`,'%Y-%m-%d %H:00')+INTERVAL(MINUTE(`DateTime`)-MINUTE(datestamp) MOD 5) interval_beginning,
DialedNumberID,
COUNT(*) call_count
FROM Calls
GROUP BY DATE_FORMAT(`DateTime`,'%Y-%m-%d %H:00')+INTERVAL(MINUTE(`DateTime`)-MINUTE(datestamp) MOD 5),
DialedNumberID
You can make this query clearer and less repetitive by defining a stored function for that ugly DATE_FORMAT() expression. But that's a topic for another day.
Finally, append
WHERE YEAR(`DateTime`) = YEAR(NOW())
AND DialedNumberID = '1234'
to the query to filter by the current year and a particular id.
This query will need work to make it as efficient as possible. That too is a topic for another day.
Pro tip: DATETIME is a reserved word in MySQL. Column names are generally case-insensitive. Avoid naming your columns, in this case DateTime, the same as a reserved word.
The average amount of calls per interval is the number of calls (COUNT(*)) divided by the minutes between the start and end of of the monitored period (TIMESTAMPDIFF(minute, period_start, period_end)) multiplied with the number of minutes in the desired interval (five in your example).
For MySQL:
select count(*) / timestampdiff(minute, date '2018-01-01', now()) * 5 as avg_calls
from calls
where `datetime` >= date '2018-01-01'
and dialednumberid = 1234;
For SQL Server:
select count(*) * 1.0 / datediff(minute, '20180101', getdate()) * 5 as avg_calls
from calls
where [datetime] >= '20180101'
and dialednumberid = 1234;
This forces the call time into 5 minute intervals. Use 'count' and 'group by' on these intervals. Using DateTime as a column name is confusing
SELECT DATEADD(MINUTE, CAST(DATEPART(MINUTE, [DateTime] AS INTEGER)%5 * - 1,CAST(FORMAT([DateTime], 'MM/dd/yyyy hh:mm') AS DATETIME)) AS CallInterval, COUNT(*)
FROM Calls
GROUP BY DATEADD(MINUTE, CAST(DATEPART(MINUTE, [DateTime]) AS INTEGER)%5 * - 1,CAST(FORMAT([DateTime], 'MM/dd/yyyy hh:mm') AS DATETIME))
Hi I have a weather database in SQL Server 2008 that is filled with weather observations that are taken every 20 minutes. I want to get the weather records for each hour not every 20 minutes how can I filter out some the results so only the first observation for each hour is in the results.
Example:
7:00:00
7:20:00
7:40:00
8:00:00
Desired Output
7:00:00
8:00:00
To get exactly (less the fact that it's an INT instead of a TIME; nothing hard to fix) what you listed as your desired result,
SELECT DISTINCT DATEPART(HOUR, TimeStamp)
FROM Observations
You could also add in CAST(TimeStamp AS DATE) if you wanted that as well.
Assuming you want the data as well, however, it depends a little, but from exactly what you've described, the simple solution is just to say:
SELECT *
FROM Observations
WHERE DATEPART(MINUTE, TimeStamp) = 0
That fails if you have missing data, though, which is pretty common.
If you do have some hours where you want data but don't have a row at :00, you could do something like this:
WITH cte AS (
SELECT *, ROW_NUMBER() OVER (PARTITION BY CAST(TimeStamp AS DATE), DATEPART(HOUR, TimeStamp) ORDER BY TimeStamp)
FROM Observations
)
SELECT *
FROM cte
WHERE n = 1
That'll take the first one for any date/hour combination.
Of course, you're still leaving out anything where you had no data for an entire hour. That would require a numbers table, if you even want to return those instances.
You can use a formula like the following one to get the nearest hour of a time point (in this case it's GETUTCDATE()).
SELECT DATEADD(MINUTE, DATEDIFF(MINUTE, 0, GETUTCDATE()) / 60 * 60, 0)
Then you can use this formula in the WHERE clause of your SQL query to get the data you want.
What you need is to GROUP BY your desired time frame, like the date and the hours. Then, you get the MIN value of the timeframe. Since you didn't specify which columns you are using, this is the most generic thing i can give.
Use as filter :
... where DATEPART(MINUTE, DateColumn) = 0
To filter the result for every whole hour, you can set your where clause to check for 00 minute since every whole hour is HH:00:00.
To get the minute part from a time-stamp, you can use DATEPART function.
SELECT *
FROM YOURTABLENAME
WHERE DATEPART(MINUTE, YOURDATEFIELDNAME) = 0
More information on datepart function can be found here: http://www.w3schools.com/sql/func_datepart.asp
I had a difficult time w/ the title, hope this is a little clearer...
I have a table of data (simplified) like so;
Date
Customer
Amount
1/1/2014
1
100.5
4/4/2014
1
122.5
2/1/2014
3
3.25
...but just short of a million records.
I would like to find the x day (let's say 90) period for each customer that has the largest total amount.
To phase the question a little differently, given all the transactions for all customers, for each customer I would like to find the 90 day period that has the largest total amount and what that total amount is in the period.
Trying to advise a brute force approach where I define all the possible ranges (or iterate over all possible ranges on the fly).
Any thoughts on a more elegant solution?
You can use a self-join for this, but the performance may not be so great:
select t.*,
(select sum(t2.amount)
from table t2
where t2.customer = t.customer and
t2.date >= dateadd(day, -90, t.date) and t2.date <= t.date
) as amount90
from table t;
There is a more efficient method in SQL Server 2012.
Here's a psuedo-code ish kind of answer that I think would work. It'd probably be really slow though.
You could have a function that calculates the number of activities provided a start date and number of days,
--function F
#userid, #startdate, #dayCount
SELECT COUNT(*)
FROM TABLE
WHERE
UserID = #userid
and date > #startDate
and date < Dateadd(#startdate, #dayCount)
and then do a max on that function?
select max(f(user, date))
from TableContainingDateRanges
I have a unique query request.
I run this query:
select * from documentationissues
where dateAdded is not null
and dateAdded >= '2013-10-09 10:37:15.483'
This will return me however many rows have been inserted since the dateAdded clause. What I am trying to do is do all of my math in the query as well.
I need to figure out how many minutes have passed since the dateAdded clause.
I need to get a count of how many rows that are returned.
I then need to figure out on average how many rows are being done on average per minute and then per hour.
And then say if there were 6,000,000 files to be done. How many days it would take to process all of the files at the average day rate.
If I ran the query right now it returned 2100 results as of today at 10:56:15 am.
So that would be 19 minutes have passed which is about 110 rows per minute and about 6600 per hour.
I'm not sure how to do all of the math in the select statement with grouping etc.
Here is another option that also includes all of the fields you were asking for:
SELECT M.RowsReturned, M.MinutesPassed,
M.RowsReturned / M.MinutesPassed AS AvgPerMinute,
M.RowsReturned / M.MinutesPassed * 60 AS AvgPerHour,
6000000 / M.RowsReturned / M.MinutesPassed / 1440 AS DaysToProcess
FROM (
SELECT COUNT(*) AS RowsReturned,
DATEDIFF(minute, '2013-10-09 10:37:15.483', CURRENT_TIMESTAMP) AS MinutesPassed
FROM documentationissues
WHERE dateAdded is NOT NULL
AND dateAdded >= '2013-10-09 10:37:15.483'
) AS M
Try this:
SELECT COUNT(*)/DATEDIFF(minute, '2013-10-09 10:37:15.483', GETDATE()) AS AvgPerMin,
COUNT(*)/DATEDIFF(minute, '2013-10-09 10:37:15.483', GETDATE()) * 60 AS AvgPerHr
from documentationissues
where dateAdded is not null
and dateAdded >= '2013-10-09 10:37:15.483'