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'

----上个月的最后一天
SELECT DATEADD(s，-1，DATEADD(mm，DATEDIFF(m，0，GETDATE())，0))
LastDay_PreviousMonth
----当月最后一天
SELECT DATEADD(s，-1，DATEADD(mm，DATEDIFF(m，0，GETDATE())+ 1,0))
LastDay_CurrentMonth
----下个月的最后一天
SELECT DATEADD(s，-1，DATEADD(mm，DATEDIFF(m，0，GETDATE())+ 2,0))
LastDay_NextMonth

----Last Day of Previous Month
SELECT DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,GETDATE()),0))
LastDay_PreviousMonth
----Last Day of Current Month
SELECT DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,GETDATE())+1,0))
LastDay_CurrentMonth
----Last Day of Next Month
SELECT DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,GETDATE())+2,0))
LastDay_NextMonth