Week of Month calculation in sql server

In SQL server you can't get the Week of Month calculation.

To archive the situation please go through given code.

Here GETDATE()='2015-05-15'

select datediff(week, dateadd(month, datediff(month, 0, GETDATE()), 0), GETDATE()) +1 AS  WEEK_OF_MONTH

In this formula e "Zero" indicates '1900-01-01'

OR

select datediff(week, dateadd(month, datediff(month, '1900-01-01', GETDATE()), '1900-01-01'), GETDATE()) +1 AS  WEEK_OF_MONTH

Step by step:

select datediff(month, 0, GETDATE())--1384 months (In sql server default start date is 1900-01-01)

select dateadd(month, 1384, 0)--2015-05-01

select datediff(week,'2015-05-01',GETDATE())+1 --Ans: 3