start    end
0	  10
10	  20
20	  30
-- пробел (30-40)
40	  50
50	  60
60	  70
-- пробел (70-90)
90	  100
100	  110
110	  120
-- пробел (120-150)
150	  160
160	  170

20	  30
40	  50
60	  70
90	  100
110	  120
150	  160

WITH "ends" AS 
(
SELECT * FROM "TestDirections"
)

SELECT 
"TestDirections"."start", 
"TestDirections"."end"
FROM "TestDirections"
LEFT OUTER JOIN "ends"
ON "TestDirections"."end" = "ends"."start"
WHERE "ends"."end" IS NULL

20	30
60	70
110	120
160	170