I tried to group my daily data by week (given a reference date) to generate a smaller panel data set.
I used postgres before and there it was quite easy:
CREATE TABLE videos_weekly AS SELECT channel_id,
CEIL(DATE_PART('day', observation_date - '2016-02-10')/7) AS week
FROM videos GROUP BY channel_id, week;
But it seems like it is not possible to subtract a timestamp with a date string in Drill. I found the AGE function, which returns an interval between two dates, but how to convert this into an integer (number of days or weeks)?
DATE_SUB may help you here. Following is an example:
SELECT extract(day from date_sub('2016-11-13', cast('2015-01-01' as timestamp)))/7 FROM (VALUES(1));
This will return number of weeks between 2015-01-01 and 2016-11-13.
Click here for documentation
Related
I am working locally with an sqllite DB. I have imported some records from teradata where there was a date field in the format of 'YYYY-MM-DD'. When i imported the records the date switched from a date to a number. I know this is a feature of sqllite and that one can access it via date(sqllite_date) when selecting it in a where clause.
My problem is that the dates now appear to be a bit odd. For example the year appears to be negative.
Is there anyway to recover this to the correct format?
Below is an example of converting a number in the database into a date
SELECT date(18386)
# -4662-03-28
SELECT datetime('now')
# 2021-02-11 10:41:52
SELECT date(sqllite_date) FROM mydb
# Returns -4662-03-28
# Should return 2020-05-04
I am very new to this area so apologies if this is a basic question. Thank you very much for your time
In SQLite you can store dates as TEXT, REAL or INTEGER.
It seems that you stored the dates in a column with INTEGER or REAL affinity.
In this case, if you use the function date(), it considers a value like 18386 as a Julian day, meaning the number of days since noon in Greenwich on November 24, 4714 B.C.
This is why date(18386) returns 4662-03-28B.C.
But I suspect that the date values that you have are the number of days since '1970-01-01'.
In this case, 18386 days after '1970-01-01' is '2020-05-04'.
So you can get the dates in the format YYYY-MM-DD if you add the value of your column as days to '1970-01-01':
SELECT date('1970-01-01', datecolumn || ' day') FROM tablename
Or by transforming your date values to seconds and treat them as UNIX time (the number of seconds since '1970-01-01 00:00:00 UTC'):
SELECT date(datecolumn * 24 * 3600, 'unixepoch') FROM tablename
Replace datecolumn with the name of your column.
Is there a way to window filter dates by a number of days excluding weekends?
I know you can use the between function for filtering between two specific dates but I only know one of the two specific dates, with the other date I would like to do is 4 days prior in business days only (not counting weekends).
An pseudo-example of what I am looking for is, given this wednesday I want to filter everything up to 4 business days beforehand:
window(z, start = as.POSIXct("2017-09-13"), end = as.POSIXct("2017-09-20"))
Another example would be if I am given this Friday's date, the start date would be Monday.
Ideally, I want to be able to play with the window value.
I've just started using SQLite, instead of SQL Server, and it doesn't seem to want to do ORDER BY, MAX() or MIN() on dates.
The Survey_Date column is a text field, so ordering it sorts it from January to December, instead of by the year. If I include date(Survey_Date) in my SELECT statement, it will sort the data by year -- but I can't override the DESC sort, and it doesn't actually display the date.
SELECT Survey_Date FROM Surveys WHERE Loc_ID = 32 ORDER BY Survey_Date;
yields results like:
01/10/2009
01/20/2013
02/05/2010
...
SELECT date(Survey_Date), Survey_Date FROM Surveys WHERE Loc_ID = 32 ORDER BY 1 ASC;
yields results like:
|01/20/2013
|02/05/2010
|01/10/2009
...
It's clearly sorting on the date correctly now, but it doesn't display the formatted date, and doesn't recognize the ASC command.
Can anyone explain what it's doing?
As already explained at least million times over this site, SQLite does not have date/timestamp type.
So if you want to sort by date, you must store them in format that sorts correctly either numerically, or lexicographically (asciibetically/unicodebetically).
The recommended format is ISO-8601, that is yyyy-mm-dd (yyyy-mm-ddTHH:MM:SS if you want a time too). This is what SQLite has some utility functions to work with, too.
Other possible formats are numeric, either number of seconds since some specific point, e.g. Unix time or number of days, e.g. (Modified) Julian day.
01/10/2009
01/20/2013
02/05/2010
They are strings, so this is correctly sorted.
SELECT date(Survey_Date), Survey_Date FROM Surveys WHERE Loc_ID = 32 ORDER BY 1 ASC;
The date function expects ISO-8601 format. It does not understand what you are giving it and returns NULL. Fully expected.
Sorting by all NULL values effectively does nothing. The rows came out sorted by accident.
In one of my tables I have datetime field in which the data in the table column is populated with something like "2016-01-07 01:33:00".
What I want to do is change ONLY the date to a random date within a range (ie: 2016-02-01 thru 2016-02-28) without changing the time. The end result might be "2016-02-13 01:33:00".
What mysql command string would accomplish this task?
Something like
UPDATE someTable SET someDate = DATE_ADD(
someDate,
INTERVAL
DATEDIFF(rangeStart, someDate) +
ROUND(RAND()*DATEDIFF(rangeEnd, rangeStart))
DAY
);
where someTable.someDate is your existing data, and rangeStart and rangeEnd are the boundaries of your target date range.
Here you take the initial date, add enough days to it to reach the range start, and then further add a random number of days no greater than the number of days in your target range.
In MsSQL it could be:
select dateadd(day,cast((RAND() * 30) as int),getdate())
Substitute getdate() with your input date.
(RAND() * 30) is used to randomly generate a number of days up to 30.
I am new to SSRS.
I have a dataset, my dataset brings data from a stored procedure.
one of the parameters of my sp is StartDate and another one is EndDate. Their type is datetime
And the table has a dateTime Column called Date.
I have two gauges and I wanna bind integer values to my gauges.
First one is the count of rows where Date < DateAdd(DateInterval.Hour,24,StartDate)
and te second is count of rows where Date > DateAdd(DateInterval.Hour,24,StartDate)
How will I write the exact script. Whatever I wrote is not working.
I appreciate any help, thanks.
You need to set the gauge Pointer value as something like:
=Sum(IIf(DateDiff(DateInterval.Day, Parameters!StartDate.Value, Fields!Date.Value) >= 1
, 1
, 0))
This is counting rows where the time difference is less than a day compared to the parameter StartDate. Just change it slightly to get those where the difference is at least a day:
=Sum(IIf(DateDiff(DateInterval.Day, Parameters!StartDate.Value, Fields!Date.Value) >= 1
, 0
, 1))
Worked fine for me in a quick test: