example greatest/least

CREATE TABLE SAT1 (DV_ID int,START_DT datetime,END_DT datetime) PRIMARY KEY (DV_ID,START_DT)
GO
CREATE TABLE SAT2 (DV_ID int,START_DT datetime,END_DT datetime) PRIMARY KEY (DV_ID,START_DT)
GO
select
    SAT1.DV_ID,
    GREATEST_DT.out as START_DT,
    LEAST_DT.out as END_DT
from SAT1 inner join SAT2 on SAT1.DV_ID=SAT2.DV_ID
cross apply ivf_greatest(SAT1.START_DT,SAT2.START_DT,NULL,NULL,NULL) as GREATEST_DT
cross apply ivf_least(SAT1.END_DT,SAT2.END_DT,NULL,NULL,NULL) as LEAST_DT
where
GREATEST_DT.out < LEAST_DT.out -- assuming an [Closed,Open) period
GO