Fast Moving Items Querry Modification with Date

Hi experts

when i run this below attached Query with One more field 'DocDate', the items are repeating,

how can i stop this item repeating issue

=========================================

SELECT t0.itemcode,max(t0.Dscription) 'Item Name', Count(T0.ItemCode) 'No. of Transaction',t3.ItmsGrpNam

from dbo.INV1 t0

INNER JOIN dbo.OINV t1 on t1.docentry = t0.docentry

left outer join dbo.OITM t2 on t0.ItemCode = t2.ItemCode

left outer join dbo.OITB t3 on t2.ItmsGrpCod = t3.ItmsGrpCod

WHERE t1.DocType = 'I' AND t1.DocDate BETWEEN '2015-06-01 13:28:15' and '2016-08-17 13:28:15' and t1.CANCELED = 'N' and t0.BaseType <> 14

GROUP BY t0.itemcode,t3.ItmsGrpNam

order by t0.ItemCode asc

===================================================================================

Regards