Return one row (DISTINCT) in a query BEX

Hi guru, i have this scenary:

one infoset on ods with timestamp field and material code

In the ODS i found many occurrence with same material code, but with many timestamp loading, es:

material timestamp

00AAA 20070301

00AAA 20070201

00BBB 20070101

in my query i want this result:

00AAA 20070301

00BBB 20070101

Can i have help for this troble ?

Thank's a lot.