I would like to add a condition in my query to filter records which has a date falling under current month. How can I achieve this? I tried to use clj-time to retrieve the current month and match it along with the DB field. But that didn't give me any luck.
Actually, it's pretty simple to determine the current month using clj-time:
(month (now)) ; number from 1 to 12
But, since you're trying to query a database, you should be interested with the beginning of the current month:
(let [t (now)]
(date-time (year t) (month t)))
This code will return you a valid DateTime object, corresponding to the beginning of the current month. You can use this object t query your SQL database:
(select objects
(where {:created [> start_of_the_current_month]}))
Related
I need to round up a month-date based on certain parameters. For example: If I have a parameter where if a day in a given month is between the 6th and the 4th of the next month, I need my query to return the next months date. Is there a way to round up the month given these parameters without hard coding case whens for every single month ever?
SELECT case when date_trunc('day',li.created_at between '2019-03-06 00:00:00' and '2019-04-06 00:00:00' then '2019-04-01' end)
FROM line_items li
If you want the beginning of the month, but offset by 4 days, you can use date_trunc() and subtract some number of days (or add some number of days). You seem to want something like this:
select dateadd(month, 1, date_trunc('month', li.created_at - interval '4 day'))
Another approach is to create a canonical "dates" table that precomputes the mapping from a given date to a new date using your rounding scheme. The mapping could be done outside of redshift in a script and the table loaded in (or within redshift using a user defined function).
For example, if I have a data set including two columns, one which shows the month as a number and the other which shows the year (result of grouping my data using GROUP BY), I want to add another column called 'Days in the month' which will display the number of days in the respective month. Is there a way I can do this? Is there some function I can add in the SELECT clause?
I want to do this since there are further calculations I need to do with that number for each row.
In SQL Server 2012+, you can use:
select day(eomonth(datecol))
eomonth() gets the last day of the month. day() just returns the day of the month -- the number of days in the month, in this case.
For older SQL Server versions, I use the following:
DAY(DATEADD(MONTH, DATEDIFF(MONTH, -1, date_column)- 1, -1))
Much less elegant than the previous answer, but functional.
In one of my SQL queries, I am using
[... and z.READ_TIMESTAMP > TIMESTAMP_TO_EPOCH(TRUNC(SYSDATE-3)]
If I want the date to be exactly 5/31/2017, will I use 'SYSDATE' (date-n) function or some other expression? or how can a modify my query for 5/31/2017
If you want the date to be exactly 5/31/2017 then use TO_DATE() or TO_TIMESTAMP() depending on which data type you need (date or timestamp). As you are using SYSDATE already the the date data type should work.
-- e.g.
select
to_date('5/31/2017','mm/dd/yyyy')
, to_timestamp('5/31/2017','mm/dd/yyyy')
from dual
...
and z.READ_TIMESTAMP > TIMESTAMP_TO_EPOCH(to_date('5/31/2017','mm/dd/yyyy'))
HOWEVER
I suspect you may want more than just a way to establish a fixed date. For example are you asking for "how do I get that last day of the previous month?" which perhaps can be satisfied by using >= and the first day of current month like this:
...
and z.READ_TIMESTAMP >= TIMESTAMP_TO_EPOCH(trunc(sysdate,'MM'))
or if it really is the last day of the previous month can be achieved with a combination of LAST_DAY() and ADD_MONTHS()
and z.READ_TIMESTAMP >
TIMESTAMP_TO_EPOCH( last_day(add_months(trunc(sysdate,'MM'),-1)) )
Without knowing a great deal more about the nature of your data and query purpose please do note that each date you use when "truncated" also has the time set to 00:00:000 - so IF you data contains time within a day other than 00:00:00 then these 2 queries might NOT produce the same result
.... datetimecolumn > to_date('05/31/2017','mm/dd/yyyy') -- "a"
.... datetimecolumn >= to_date('06/01/2017','mm/dd/yyyy') -- "b"
For example "a" the entire 24 hour duration of 05/31/2017 would be included in the results, but for example "b" that same 24 hour duration would be excluded from results. In my experience the last day of any month isn't really the best method for locating date/time based data, instead usually it is the first day of the next month that produces the correct result.
I know this one is pretty easy but I've always had a nightmare when it comes to comparing dates in SQL please can someone help me out with this, thanks.
I need to get the month and year of now then compare it to a date stored in a DB.
Time Format in the DB:
2015-08-17 11:10:14.000
I need to compare the month and year with now and if its > 12 months old I will increment a count. I just need the number of rows where this argument is true.
I assume you have a datetime field.
You can use the DATEDIFF function, which takes the kind of "crossed boundaries", the start date and the end date.
Your boundary is the month because you are only interested in year and month, not days, so you can use the month macro.
Your start time is the value stored in the table's row.
Your end time is now. You can get system time selecting SYSDATETIME function.
So, assuming your table is called mtable and the datetime object is stored in its date field, you simply have to query:
SELECT COUNT(*) FROM mtable where DATEDIFF(month, mtable.date, (SELECT SYSDATETIME())) > 12
I just don't know how to go about this.
I designed a program that uses MS Access as its database. I have a field for month and year (the field data type is text) where user can register details. The program will register the month and year the user have chosen e.g month= September, year=2011.
My problem now is how to chose a range of data to view by the user using the month and year as a criteria e.g the User may want to view data range from (September 2011 to July 2013).
I couldn't figure out even how to try. Help will be highly appreciated.
Perhaps you could change your application logic to store the month and year as their respective numbers rather than text and change the field data types to numeric.
You could then construct a DateTime object from them, for example September would be 9 and you could use code like the following:
var startDate = new DateTime(year, month, 1); // get year and month as integers from database, uses the first as the date
var endDate = new DateTime(year, month, 10); // change the date but keeps the month and year the same
var endDate2 = startDate.AddMonths(1); // adds 1 month to the date
Alternatively, you could try using a calendar control to allow the user to select two dates instead of building it from a number of fields. Depending on what you are using this could be achieved a number of ways, for example in ASP.Net or WPF you could use two calendar controls and just use their SelectedDate properties as your range.
A range is from a startpoint until an end point. For the startpoint you can add automatically the first of Month. For the endpoint is it more complicated because there is no fix endpoint. What you can do is following:
Write an array that contains for each month the days (e.g. 30 or 31). Except for Febrauary there is a fix pattern.
for Febrauary use the selected year to check is the year a leap year or not. If not add 28, else add 29.
After that create the date string for your SQL:
Startdate 1.9.2011. Do for the entdate the same.
After that, I think you can use the keyword between in your SQL query.
You can assume that everything is entered on the first day of each month. I would pull the information using a query to the database.
select * from [tablename] where DateSerial([colYear], [colMonth], 1) between DateSerial([fromYear], [fromMonth], 1) and DateSerial([toYear], [toMonth], 1)
In this question are some ways to do this:
First. Filter the dates in a range assuming that you use a date like '07-12-2012'
i.e. September 2011 to July 2013
Where DateColumn > '09-01-2011' and DateColumn < '07-31-2013'
OR
Specify a Date and a Year
Where month(DateColumn)='1' and year(DateColumn)='2016'
Note:
There are many ways to do this.
You can Manipulate your statement depending on your desired output.