What is a simple and efficient way to find rows with time-interval overlaps in SQL?

Question

I have two tables, both with start time and end time fields. I need to find, for each row in the first table, all of the rows in the second table where the time intervals in

Answer 1

And what, if you want to analyse such an overlap on a minute precision with 70m+ rows? the only solution i could make up myself was a time dimension table for the join

else the dublicate-handling became a headache .. and the processing cost where astronomical