I have a table called message. I try to select a message from a table only when man_send_id and person_receive_id are different.
I can choose person_send_id and person_receive_id correctly.
However, I do not know how to select a message.
I was thinking about using Select in a Select, but I don't know how to implement it, or if this is the right way to do it.
SELECT DISTINCT person_send_id, person_receive_id
FROM `message`
WHERE person_send_id = 21 OR person_receive_id = 21
//AND SELECT message FROM `message` when these criteria are met
Message table
message_id
message
person_send_id
person_receive_id
Here are my table data.

I want to select only the first message in which person_send_id and person_receive_id are repeated.
Therefore, if I send 10 messages to the same person, I only want to capture only the record with the message, in this case "Hello", for example