how to get date of 1st week of current month - sql

I have to get/create date (date of first week) from the user input of day name
Examples-
if input saturday then date should be 7 (for current month 1st saturday)
if input sunday then date 1 (current month 1st sunday)
I am having to use lot of logic to get the date but couldn't get exact output
any suggestions on how to come up with the SQL query for such a function ?

If you are using SQL*plus in Oracle then the code will be as :
select next_day(sysdate,'&d')-7 from dual;
If any update required please do inform.
okay i have a link hereby where you can understand this and try to do
Your answer!!!

Try this.
SELECT DATEPART(dw,DATEADD(m, DATEDIFF(m, 0, GETDATE()), 0))
input: if getdate() returns date in jan 2017
output: 1
input:if getdate() returns date in jan 2017
output: 4

Related

not getting previous month record using datepart in sybase

Using below depart syntax to fetch for previous month record, it is working fine till previous year,however it is giving 0 value in January month.How can we get pervious month with date part even if year is change ?
DATEPART(month(GETDATE()) -1
I understand that I used another type of DB, but I want to give a hint. I am using sql server 2019.
Firstly, you need to substitute date and only then take datepart from it.
Queries:
--dateadd -1 would subtract 1 from current month
--(Jan - 1 2022), would be December 2021
select datepart(month, dateadd(month, -1, getdate()))
--also date add covers internally the problem with 30,31 days.
--May always has 31 days, April 30. So -1 subtraction from 31th of May,would result in 30th of April.
select dateadd(month, -1, cast('2021-05-31 10:00:00' as datetime))

Start of the week (Monday) - Query gives an incorrect date

I have this query to get the start of the week (Monday) for the current date. It breaks when the date is first of the month and a Sunday. Not sure how to solve this issue. Any help would be highly appreciated. Thanks.
DATEADD(wk,DATEDIFF(wk,0,'2017-01-01'),0)
This is happening because you are finding the no. of weeks from date 0 to the supplied date. 0 is actually '1900-01-01' which was a Monday. Therefore,DATEDIFF finds the number of completed weeks from this date until the supplied data. Thats why DATEDIFF for March 27 2016 returns 6065 (as it is the end of a week) and March 26 2016 returns 6064 (as it is still not the end of a week).
This is already explained in this link - Get first day of the week
Try the code mentioned below. Is that what you are looking for?. Let me know if this works
declare #date date = '2017-01-01'
select case when dateadd(dd,-datepart(dw,#date)+2,#date) < dateadd(dd,-day(#date)+1,#date)
then #date else dateadd(dd,-datepart(dw,#date)+2,#date) end as firstdayoftheweek

Get Year of Previous Month (For Jan 1st)

I'm currently building a YTD report in SSRS. I'm looking to edit the default "FROM" date in a calendar selection.
I'm looking to retrieve January 1st of the previous months year. For example:
(If it's Feb 16th, 2016 .. the result should be 1/1/2016
If it's Jan 10th, 2016 .. the result should be 1/1/2015)
I built this to retrieve the current year for jan 1st, but it causes issues if we're in January because I need it to retrieve the year of the previous month (in that case it would be 2015, not 2016).
Thanks!
Try this, it should work
=DateAdd(DateInterval.Month,-1,DateSerial(Year(Today), Month(Today), 1))
UPDATE:
Based on your comment I've created this expression. It is not tested but should work.
=IIF(Today.Month>1,
DateAdd(DateInterval.Month,-1,DateSerial(Year(Today), Month(Today), 1)),
DateAdd(DateInterval.Year,-1,DateSerial(Year(Today), Month(Today), 1))
)
Let me know if this helps.
select cast(cast(year(dateadd(mm, -1,getdate())) as varchar)+'-01-01' as date)
replace getdate() with which ever field you're basing this calculation on.
for testing:
select cast(cast(year(dateadd(mm, -1,'2015-01-22')) as varchar)+'-01-01' as date)
select cast(cast(year(dateadd(mm, -1,'2016-02-01')) as varchar)+'-01-01' as date)
select cast(cast(year(dateadd(mm, -1,'2015-12-12')) as varchar)+'-01-01' as date)
We want to use Date Serial which has the forma
=DateSerial(YYYY,MM,DD)
The Month is always January
The day is always the first
If the month is January, it's last year. Otherwise, it's this year.
So, assuming we have an SSRS report with a parameter called Date , we can create a new field for your January date as follows:
=iif(Month(Parameters!Date.Value)=1,
dateserial(Year(Parameters!Date.Value)-1,1,1),
dateserial(Year(Parameters!Date.Value),1,1))
if you want to do this in the query with T-SQL (version 2012) or later:
case when month(#DATE) = 1
then DATEFROMPARTS(YEAR(#DATE)-1,1,1)
else DATEFROMPARTS(YEAR(#DATE),1,1)
end
OR, in earlier versions
CASE WHEN MONTH(#DATE) = 1
THEN CAST(CAST((YEAR(#DATE)-1)*10000 + 101 AS CHAR(8)) AS DATE)
ELSE CAST(CAST((YEAR(#DATE)*10000+ 101) AS CHAR(8)) AS DATE)
END

Oracle - How to get first Monday of the year?

How to get first Monday of the year?
select TRUNC(date'2015-01-01','YYYY')
,NEXT_DAY(TRUNC(date'2015-01-01','YEAR')+1,'MONDAY')
from dual;
01-JAN-2015 05-JAN-2015
To account for the possibility of the year starting on a Monday, you need to go back to the last day of the previous year, before going forward to the next Monday; for the current year:
next_day(trunc(sysdate, 'YYYY') - 1, 'Monday')
SQL Fiddle demo. This gives the first Monday of 2007 as January 1st; without the -1 adjustment it would say the 8th.
Try this:
select next_day(round(sysdate,'yyyy'),'mon')
from dual;

Get 1st Day of Week (Sunday)

I have this formula in my column to calculate the start date of a given week :
dateadd(week,[Week]-(1),
dateadd(day,(-1),
dateadd(week,
datediff(week,(0),
CONVERT([varchar](4),[Year],(0))+'-01-01'),
(1))))
Where Week and Year are other fields like 38 and 2012
Problem is, it calculates the start date of week 38/2012 as a monday (17th Sept), I would like it to be a sunday instead (16th Sept) is this possible?
Many thanks.
This will return you the first day of the week, given a week number and a year, assuming that the first day of the week is a Sunday.
Standard exclusions apply, e.g. don't try year 1499.
declare #tbl table ([Week] int, [Year] int)
insert #tbl select 38,2012
union all select 1,2012
union all select 0,2012
union all select 1,2013
select DATEADD(
Week,
[Week]-1,
DATEADD(
Day,
(8-##datefirst)-DATEPART(dw, CAST([Year]*10000+101 AS VARCHAR(8))),
CAST([Year]*10000+101 AS VARCHAR(8))))
from #TBL
Result
2012-09-16 00:00:00.000
2012-01-01 00:00:00.000
2011-12-25 00:00:00.000
2012-12-30 00:00:00.000
Note that the Week number starts from 1, and if the week doesn't start on a Sunday, then the first day of that week could end up in an earlier year (row #4). Because the Weeks are relative, you can use Week 0, -1 etc and it will still give you a result (row #3), rightly or wrongly.
You may also notice I used a different method to create a date out of the year, just as an alternative.
The (8-##datefirst) portion of the query makes it robust regardless of your DATEFIRST setting.
If you want the first day of the week to be Sunday you could change your database to make it so, using the DATEFIRST setting.
function getFirstDateOfThisWeek(d)
{
var TempDate = new Date(d || new Date());
TempDate.setDate(TempDate.getDate() + (#Config.WeekStartOn - 1 - TempDate.getDay() - 7) % 7);
return TempDate;
}
var StartDate = getFirstDateOfThisWeek(new Date()); //1st date of this week