tsql - SQL: Retrieve Values if different from prior date -

i have following table:

date_            value_ 2013-07-13       100055 2013-07-14       100055 2013-07-15       120060 2013-07-16       115040 2013-07-17       115040 2013-07-18       130005 

i return first value in results , every change.

desired output:

date_            value_ 2013-07-13       100055 2013-07-15       120060 2013-07-16       115040 2013-07-18       130005 

thanks help!

you looking group by clause , min function

select min(date_) date_, value_ tab group value_