How to compare two different data tabels

Deal All

I have two different data tabels.
Datatabel1 contains the columns-SaleDate,DistributorCode,InvoiceNo,SaleQty,SaleValue,ReturQty,ReturnValue,GPRAmount,TTSAmount.
Datatabel2 contains the columns-SaleDate,DistributorCode,InvoiceNo,SaleQty,SaleValue,ReturQty,ReturnValue,GPRAmount,TTSAmount.
I need the result of unmatched rows by comparing only first 3 columns(i.e SaleDate,DistributorCode,InvoiceNo,)....
Ex:
If my Datatabel1 contains the following rows
SaleDate       DistributorCode  InvoiceNo      SaleQty,SaleValue         ReturQty                ReturnValue        GPRAmount          TTSAmount
2013-09-10   883833               10                 586.000000        ...