sone useful sql functions

Last day of year
DATEADD(yyyy,datediff(yyyy,0,GETDATE()),0) -1
First day of year
DATEADD(yyyy,datediff(yyyy,0,GETDATE()),0)
Last day of quarter
DATEADD(QQ,datediff(QQ,0,GETDATE()),0) -1

Last day of week
DATEADD(week,datediff(week,0,GETDATE()),0) -1