Table: Calls
+-------------+---------+ | Column Name | Type | +-------------+---------+ | from_id | int | | to_id | int | | duration | int | +-------------+---------+ This table does not have a primary key, it may contain duplicates. This table contains the duration of a phone call between from_id and to_id. from_id != to_id
Write an SQL query to report the number of calls and the total call duration between
each pair of distinct persons (person1, person2) where person1
< person2.
Return the result table in any order.
The query result format is in the following example:
Calls table: +---------+-------+----------+ | from_id | to_id | duration | +---------+-------+----------+ | 1 | 2 | 59 | | 2 | 1 | 11 | | 1 | 3 | 20 | | 3 | 4 | 100 | | 3 | 4 | 200 | | 3 | 4 | 200 | | 4 | 3 | 499 | +---------+-------+----------+ Result table: +---------+---------+------------+----------------+ | person1 | person2 | call_count | total_duration | +---------+---------+------------+----------------+ | 1 | 2 | 2 | 70 | | 1 | 3 | 1 | 20 | | 3 | 4 | 4 | 999 | +---------+---------+------------+----------------+ Users 1 and 2 had 2 calls and the total duration is 70 (59 + 11). Users 1 and 3 had 1 call and the total duration is 20. Users 3 and 4 had 4 calls and the total duration is 999 (100 + 200 + 200 + 499).