按MeterID分组，按CurrentReadDate时间倒序，取第一行

 select * from (
 select Row_number() over( PARTITION  BY MeterID order by a.CurrentReadDate desc) Idx,MeterID,a.CurrentReadDate,a.CurrentReadDegree from Wygl_Charge_HouseMeterDegrees a
 ) b
 where b.Idx=1