从另一张表中查询两列值的SQL查询

Question

Thank in advance for i know my problem definitely is going to resolve here within next few minutes.

i have two tables one for user data and other for request table. request table contains the records of all request given by a user to another user. these user details is carrying by table one user .

now need to retrieve data from request table with the name of user who sends request and user who receive the request instead of request_by ID and request_to id

As All of you knows that, i am beginner of MySQL so don't mind on my query as below.

select r.*
     , u.user_name as request_by
     , u.user_name as request_to
from req_value r 
left join user u on r.req_to = u.user_id
                 or r.req_by = u.user_id

Answer 1

You need 2 INNER JOIN s with the user table to get name for 2 different columns: req_to and req_by

select r.*
     , u1.user_name as request_by
     , u2.user_name as request_to
from req_value r  
join user u1 on r.req_by = u1.user_id
join user u2 on r.req_to = u2.user_id