Here's how to get all of the a_imei
clones:
SELECT c1.*
FROM calls As c1
JOIN calls As c2
ON c1.a_imei = c2.a_imei
AND c1.a_phone != c2.a_phone
AND c1.call_start_time < c2.call_end_time
AND c1.call_end_time > c2.call_start_time
ORDER BY c1.a_imei, c1.call_start_time, c1.call_end_time
Here's how to compare both the "a"s and "b"s together:
SELECT c1.*, c2.*
FROM calls As c1
JOIN calls As c2
ON c1.call_start_time < c2.call_end_time
AND c1.call_end_time > c2.call_start_time
AND ( (c1.a_imei = c2.a_imei AND c1.a_phone != c2.a_phone)
OR (c1.a_imei = c2.b_imei AND c1.a_phone != c2.b_phone)
OR (c1.b_imei = c2.a_imei AND c1.b_phone != c2.a_phone)
OR (c1.b_imei = c2.b_imei AND c1.b_phone != c2.b_phone)
)
ORDER BY c1.a_imei, c1.call_start_time, c1.call_end_time, c1.b_imei