Using sql server Get Today Week no of day and Fist and Last day of week

 Select GETDATE() AS 'Today', DATEPART(Week,GETDATE()) AS 'Week No of Today', 
DATEADD(DAY , -DATEPART(WEEKDAY,(DATEADD( DAY , 7-DATEPART(WEEKDAY,GETDATE()),GETDATE())))
+ (7-DATEPART(WEEKDAY,GETDATE()))+1 ,GETDATE()) 'First Day Of This Week',
DATEADD(DAY , 7-DATEPART(WEEKDAY,GETDATE()),GETDATE()) AS 'Last Day Of Week'



Getdate() returns today's date

datepart(week,getdate()) returns current week no