This post is to provide scripts to identify FIRST and LAST usages for a given date.
--How to get first day of a month
Declare @Date Datetime = GETDATE()
SELECT DATEADD(month, DATEDIFF(month, 0, @date), 0);
--How to get Last day of a month
Declare @Date Datetime = GETDATE()
SELECT DATEADD(DAY,-1,DATEADD(mm, DATEDIFF(m,0,@Date)+1,0));
--How to get first day of a Calendar Year
DECLARE @DATE DATETIME = GETDATE()
SELECT DATEADD(YY, DATEDIFF(YY,0,@DATE), 0) AS STARTOFYEAR
--How to get Last day of a Calendar Year
DECLARE @DATE DATETIME = GETDATE()
SELECT DATEADD(YY, DATEDIFF(YY,0,@DATE) + 1, -1) AS ENDOFYEAR
I will add more usages of FIRST/LAST day to the above list as I come across in future.
SQLZealots 
–first day of a month
select DATEADD(DAY,1,EOMONTH(GETDATE(),-1))
–Last day of a month
select EOMONTH(GETDATE())
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Hi Vinuraj, Thanks for reading and sharing the script.
EOMONTH() function has been introduced in SQL Server 2012. My intention is to provide script which works in all SQL Server versions.
However, a good point and I will definitely add this as a separate script in my post.
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