Try (not tested much)

lnQuarterBegin = DATE(YEAR(ldDate), (QUARTER(ldDate)-1)*3 + 1, 1) 

>
>
>I have a date and i want the beginning of a quarter.
>
>eg1 = 01/01/2009
>eg2 = 23/02/2009
>eg3 = 15/04/2009
>
> beginning of a quarter( eg1 )
> beginning of a quarter( eg2 )
> beginning of a quarter( eg3 )
>
>
>01/01/2009 Give 01/01/2009
>23/02/2009 Give 01/01/2009
>15/04/2009 Give 01/04/2009
>
>
>
>thank in advance
>
>bernhart