如何查询一个表的同一列中的两个不同对象，这些对象与另一个表中的不同列相关？

Question

I have the tables

people

id INTEGER

name

phone_number

PRIMARY KEY(id)

phone_calls

id INTEGER

caller_number

receiver_number

year

month

day

duration

PRIMARY KEY(id)

I want to take the information like

name1 (as caller)	name2 (as receiver)
nikolas	mary
kostas	bob

i managed with SELECT name, caller_number FROM people JOIN phone_calls ON people.phone_number = phone_calls.caller_number WHERE year = AND month = AND day = AND duration =; to get

name as caller	caller_number
nikolas	6999999999
kostas	688888888

or with SELECT name, receiver_number FROM people JOIN phone_calls ON people.phone_number = phone_calls.receiver_number WHERE year = AND month = AND day = AND duration =; to get

name as receiver	receiver_number
mary	6777777777
bob	6555555555

or with SELECT caller,receiver_number FROM phone_calls WHERE year = AND month = AND day = AND duration; to get

caller_number	receiver_number
6999999999	6777777777
688888888	6555555555

or with SELECT name, receiver_number FROM people JOIN phone_calls ON people.phone_number = phone_calls.caller_number WHERE year = AND month = AND day = AND duration =; to get

name as caller	receiver_number
nicolas	6777777777
kostas	6555555555

so i get the name at the telephone number of the caller or the name and the telephone number of the receiver, but not name of the caller and name of the receiver in the same place.

Answer 1

You need 2 joins to get both caller and receiver's name. For example

SELECT caller.name, receiver.name
FROM phone_calls
JOIN people caller ON caller.phone_number = phone_calls.caller_number
JOIN people receiver ON receiver.phone_number = phone_calls.receiver_number
WHERE <your conditions>