SELECT Date, DatePart(hour,Date) as Hr, reading FROM bin1_empty A WHERE EXISTS( (SELECT Min(Date) as date_B FROM bin1_empty B WHERE DatePart(hour,A.Date) = DatePart(hour,B.Date) HAVING B.Date_B = A.Date) OR EXISTS( SELECT Min(Date) as date_C FROM bin1 C WHERE DatePart(hour,A.Date) = DatePart(hour,C.Date) HAVING C.Date_C = A.Date)but it has error shown in image.