Возможно
DELETE FROM T1
WHERE (T1.Date, T1.IPin, T1.IPout, T1.IsIN) IN
(SELECT Q1.Date, Q1.IPin, Q1.IPout, Q1.IsIN
FROM (select T2.Date, T2.IPin, T2.IPout, T2.IsIN , Sum(T2.T_ALL)
from T1 AS T2
group by T2.Date, T2.IPin, T2.IPout, T2.IsIN
HAVING Sum(T2.T_ALL)<1) AS Q1(Date, IPin, IPout, IsIN , T_ALL)))