day:
table.date=currentdate or table.date = dateadd('yyyy',-1,currentdate)
weekly depends on how you are defining it but one way would be like kevray suggests.
This would give you a full week for last year and possibly a partila week for the current year
datepart('ww',currentdate)=datepart('ww',table.datefield) and (datepart('yyyy',table.datefield) = datepart('yyyy',currentdate) or datepart('yyyy',table.datefield) = datepart('yyyy',dateadd('yyyy',-1,currentdate)))