max in group by

kindly tell me why max date not showing when i m using group by.

data :

BEGIN OF GetMaxDate OCCURS 1,

matnr like a305-matnr, " matnr

datab like a305-datab, " validFrom

knumh like a305-knumh , " RecNo

kunnr like a305-kunnr, " CustomerNo

vtweg like a305-VTWEG,"channel

*PLTYP like a304-pltyp ," Pricelist type

END OF GetMaxDate.

SELECT MATNR MAX( DATAB ) as ValidFrom from A305 INTO CORRESPONDING FIELDS OF TABLE GETMAXDATE GROUP BY MATNR

but result shows date like 00:0000:00