Difference in datetime stamps impala - sql

I want a query that shows a time difference in months or days in Impala
How can I do this?
start 2017-11-29 19:45:00 - end 2018-11-29 21:30:00
I know that month_between and datediff shows the month of datediff but how do I make it so it also takes the year into count when counting the days / months?
For the above example, I want to to display either
month_between - 12.2 months - equivalent to the month calculation of the timestamp - might be a little off cause I did it by hand / 30 days
days_between - 366 days

not sure if you tried DATEDIFF or not , but it already gives you the dates difference in days :
select datediff(endddaate, startdate)
from tablename

Related

How to subtract multiple day range from current date

Using Teradata -
I know I can subtract days from current date by Current_date -7, but I need to subtract multiple day options from a date field. Say my data field is Completed_Date and I need to pull any dates that are from 7 - 14 days prior to that date. So today being 5/20/2022, it will pull records with completed dates from 7 -14 days ago - 5/6/2022 - 5/13/2022
Hope I've made that clearer than mud...
Thanks,
Kim

How to Find the Interval Between Two Dates in PostgreSQL

I have a 'test_date' column in 'test' table in Postgres DB, ex - (2018-05-29)
I need to calculate difference between current date and that date column and return the result as days, months, years.
I tried -
select (current_date - test_date) from test;
but it returns the values as days. but I need the result as days, months, years.
How to convert it properly ?
The age() function returns the value as an interval rather than the number of days:
select age(current_date, test_date)
If you use a timestamp then you'll get a `interval' back:
select justify_interval(date_trunc('day', current_timestamp) - test_date)
The date_trunc() is there to set the time part of the timestamp to 00:00:00. By default that would return an interval with only days in it. The justify_interval() will then "normalize" this to months, weeks and days.
E.g. 0 years 7 mons 28 days 0 hours 0 mins 0.0 secs

How to get start & end of same week last year in DB2 using SQL?

I have a weekly report that uses these date parameters:
SELECT *
FROM TABLE
WHERE DATE_FIELD BETWEEN (CURRENT DATE - 8 DAYS) AND (CURRENT DATE - 2 DAYS)
This runs on Mondays to gather the previous week's data (Sun-Sat). What I want now is to run this for the same week of the previous year.
So for example, if the code above runs on Mon 29/06/20, it returns data from Sun 21/06/20 - Sat 27/06/20, i.e. week 26 of 2020. I want it to return data from Sun 23/06/19 - Sat 29/06/19, i.e. week 26 of 2019.
The report runs automatically so I can't just plug in the exact dates each time. I also can't just offset the date parameters to -357 and -367 days, as this gets thrown off by leap years.
I've searched for solutions but they all seem to rely on the DATEADD function, which my DB2 database doesn't recognise.
Does anyone know how I can get the result I'm looking for, please? Any advice would be appreciated! :)
The easiest way to do this is to build a calendar or dates table...(google sql calendar table)
Among the columns you'd have would be
date
year
month
quarter
dayofWeek
startOfWeek
endOfWeek
week_nbr
You can use the week() or week_iso() functions when loading the table, pay attention to the differences and pick the best fit for you.
Such a calendar table makes it easy to compare current period vs prior period.
If you assume that all years have 52 weeks, you can use date arithmetic:
SELECT *
FROM TABLE
WHERE DATE_FIELD BETWEEN (CURRENT DATE - (8 + 364) DAYS) AND (CURRENT DATE - (2 + 364) DAYS)
Because you want the week to start on a Monday, this doesn't have to take leap years into account. It is subtracting exactly 52 weeks -- and leap years do no affect weeks.
This gets more complicated if you have to deal with 52 or 53 week years.
A little bit complicated, but it should work. You may run it as is or test your own date.
SELECT
YEAR_1ST_WEEK_END + WEEKS_TO_ADD * 7 - 6 AS WEEK_START
, YEAR_1ST_WEEK_END + WEEKS_TO_ADD * 7 AS WEEK_END
FROM
(
SELECT
DATE((YEAR(D) - 1)||'-01-01')
+ (7 - DAYOFWEEK(DATE((YEAR(D) - 1)||'-01-01'))) AS YEAR_1ST_WEEK_END
, WEEK(D) - 2 AS WEEKS_TO_ADD
FROM (VALUES DATE('2020-06-29')) T(D)
);
The intermediate column YEAR_1ST_WEEK_END value is the 1-st Sat (end of week) of previous year for given date.
WEEKS_TO_ADD is a number of weeks to add to the YEAR_1ST_WEEK_END date.

How to subtract 13 weeks from a date in PL SQL?

I have a date in sql which will always fall on a Monday and I'm subtracting 13 weeks to get a weekly report. I am trying to get the same 13 week report but for last year's figures as well.
At the moment, I'm using the following:
calendar_date >= TRUNC(sysdate) - 91
which is working fine.
I need the same for last year.
However, when I split this into calendar weeks, there will also be a partially complete week as it will include 1 or 2 days from the previous week. I need only whole weeks.
e.g. the dates that will be returned for last year will be 14-Feb-2015 to 16-May-2015. I need it to start on the Monday and be 16-Feb-2015. This will change each week as I am only interested in complete weeks...
I would do this:
Get the date by substracting 91 days as you're already doing.
Get the number of the day of the week with TO_CHAR(DATE,'d')
Add the number of days until the next monday to the date.
Something like this:
SELECT TO_DATE(TO_DATE('16/05/2015','DD/MM/YYYY'),'DD/MM/YYYY')-91 + MOD(7 - TO_NUMBER(TO_CHAR(TO_DATE(TO_DATE('16/05/2015','DD/MM/YYYY'),'DD/MM/RRRR')-91,'d'))+1,7) d
FROM dual
next_day - returns date of first weekday named by char.
with dates as (select to_date('16/05/2015','DD/MM/YYYY') d from dual)
select
trunc(next_day( trunc(d-91) - interval '1' second,'MONDAY'))
from dates;
I want to get next monday from calculated date. In situation when calculated date is monday i have to move back to previous week ( -1 second).

Teradata Change format of Week Number

I'm pretty new to SQL so I hope this isn't a dumb question, tried to google but couldn't find anything.
I'm summing sales of departments per week in SQL and am using TD_SYSFNLIB.WEEKNUMBER_OF_YEAR (trans_dt) to get the week number.
I think everything is working except I'd like to change the format of the weeks to the start date of the week, e.g. week 1 = 1/4/15
Also, i'm not sure how to handle the very first of the year week 0 since I think that should be grouped up with week 52 of last year.
The following date math trick should get you Beginning of Week as an actual date without having to join to the SYS_CALENDAR view or using a function:
SELECT CURRENT_DATE - ((CURRENT_DATE - DATE '0001-01-07) MOD 7) AS BOW;
Starting with TD14 there's NEXT_DAY which returns the following weekday, if you subtract 7 days you get the previous day:
next_day(trans_dt - 7, 'sunday')