How to fetch data from 2 different tables in mysql -

i have 2 tables:

subscriber_detail  subscriberid | merchant_id  23           |  24  user_detail  user_id | user_registeredid  23      | 1001001 24      | 1001002 

need fetch user_registeredid user_login table subscriberid , merchant_id subscriber_detail

select  sub.user_registeredid subscriberregisteredid,         mer.user_registeredid merchantregisteredid    subscriber_detail s         join user_detail sub on s.subscriberid = sub.user_id         join user_detail mer on s.merchant_id = mer.user_id 

you need join both tables , table user_detail should join 2 times because there 2 columns in table subscriber_detail referenced it.

if 1 column nullable, left join should used instead.

select  sub.user_registeredid subscriberregisteredid,         mer.user_registeredid merchantregisteredid    subscriber_detail s         left join user_detail sub on s.subscriberid = sub.user_id         left join user_detail mer on s.merchant_id = mer.user_id