I've been having a look around but I can't seem to find anything that answers this question. I want to calculate the date for the last week of every month. For example, the date for the last week of April 2021 is 26-04-2021. I want a date, not a week number.
I use Google Big Query, I do have a calendar table I could use to extract year and month.
Thanks,
Emily
Try date_trunc:
SELECT date_trunc(last_day(month1st, month), week(monday))
from unnest(GENERATE_DATE_ARRAY('2021-01-01', '2021-12-01', interval 1 month)) AS month1st;
Related
I want to find out the previous weeks's last day in Teradata SQL using Sunday as the last day of the week. For example, today is Friday 1/27, so the last week ended on Sunday (1/22) and I would want to return 2023-01-22.
Other examples:
If current date is '2023-01-02', then the output I require is '2023-01-01'
If current date is '2023-01-18', then the output I require is '2023-01-15'
With Hive query I would use:
date_sub(current_date, cast(date_format(current_date, 'u') as int));
What would the equivalent be in Teradata? I've tried using the code below but it seems to return the date of the closest Sunday instead of the date of the previous Sunday.
SELECT ROUND(current_date, 'd') (FORMAT 'yyyy-mm-dd');
There are several ways:
Probably the best one is one of the built-in functions to return the previous xxxday <= the input date:
Td_Sunday(Current_Date - 1)
Or the function to return the next xxxday > input date:
Next_Day(Current_Date - 8, 'sun')
Truncating is least understandable:
Trunc(Current_Date, 'IW') -1
TRUNC supports three variations, only IW is usable, but restricted to Monday as week start:
IW: the Monday of the ISO week
WW: the same day of the week as January 1st of the year
W: the same day of the week as the first day of the month
You can use the trunc function to return the first day of the a week, month, ect.
select trunc(current_date -7 ,'IW')
Current date today is 2023-01-27. This will return 2023-01-15, the previous Sunday.
EDIT: Sorry, meant to use the ISO week. As Dnoeth points out, the regular week option doesn't work consistently (which I didn't know, never used it for this before). Anyhoo, his answer is better than mine...
Currently have rows aggregated by week number.
SELECT to_char(date, 'IYYY-MM-IW') AS week, from TABLE GROUP BY week
The results will show the form "2021-07-29". Is it possible to change the week number such that it is the number week of the month (instead of year).
For example, instead of "2021-07-29", we convert to "2021-07-04" since the 29th week of the year is actually the 4th week of the month.
Quote from the manual
W week of month (1–5) (the first week starts on the first day of the month)
So you can use:
to_char(date, 'YYYY-MM-W')
For e.g 2021-10-18 this yields 2021-10-3 (third week in October)
I have a table where I only have week number and year (and another not timing variables).
Week number : I have it as 1, 2,3,4,5 up to 53.
Year : 2020, 2021, etc
Therefore for ever week-year I have a row.
Goal:
I have seen that in Tableau you can show by week too but showing the first day of the week (see screenshot).
How to create/convert a column/existing columns so that first day of week is shown as date instead.
Thanks,
You can do this. Try this formula:
DATETRUNC('week',DATEPARSE("w-yyyy",STR([Week])+"-"+ STR([Year])))
DATEPARSE converts your week and year to a date.
DATETRUNC returns the first date of each week.
I need to convert Week to start with Sunday (range 1-53, with a Sunday in this year)
Ex. DATE_PART(w,'2020-01-05') (Sunday)
This should return 2 instead of 1.
Thanks in advance.
If you wish to obtain the Week Number where a week starts on Monday instead of Sunday:
Subtract one day to the date being convert to the Week Number
So, use:
DATE_PART(w, date_field - INTERVAL '1 DAY')
This returns the Week Number of the 'previous day'.
Unfortunately, it won't work for the first day of the year, which will appear to be the last day of the previous year. Depending on how your organization treats the first/last weeks of the year, this might be okay.
If that is not satisfactory, then you could write your own User-Defined Function (UDF) and code it to return the values you desire.
I have a condition here in which I will have total experience in terms of month and year. For example, two drop down will be there for asking total number of experience in month and year. So if I am working from 1 Jan 2012, then I will write total experience as 3 year and 11 months. Now I have to convert this 3 year and 11 months into date format so that I can save this into database
You could use java.util.Calendar:
Calendar calendar = Calendar.getInstance();
calendar.add(Calendar.MONTH, month);
calendar.add(Calendar.YEAR, year);
Date date = calendar.getTime();
As a word of caution, the day field would be set to today's date. Check the intended behaviour if the current day is outside of the bounds for the target month. For example, setting the month to February when calendar has a day field of 30. It might be wise to set the day to a known, valid value for every month (eg: 1) before setting the month and year.
Use DATE_SUB() function:
Try this:
SELECT DATE_SUB(DATE_SUB(CURRENT_DATE(), INTERVAL 3 YEAR), INTERVAL 11 MONTH);
You can use mysql's date_sub() function or <date> - interval <expression> unit syntax to subtract an interval from a date.
select date_sub(curdate(),interval '3-11' YEAR_MONTH) as start_date
UPDATE:
Following the conversation between the OP and #eggyal, the OP need to replace the period in the incoming data with - and construct an insert statement as follows:
insert into mytable (...,join_date,...) values (...,date_sub(curdate(),interval '3-11' YEAR_MONTH),...)