mysql join query order by two columns

Question

I am trying to join two tables and in both tables I have 2 same column names like agent_id and date both tables have agent_id and date actually I join tables based on agent_id a

Answer 1

    SELECT sr.*,pm.paid
    FROM `sales_report` as sr
    INNER JOIN `payments` as pm
    ON sr.`agent_id`=pm.`agent_id` 
    ORDER BY sr.date, pm.date

Will get you date from first table and order by 1st table date then 2nd table date.

Answer 2

    SELECT * FROM
    (
         SELECT sr.date
            FROM `sales_report` as sr
         UNION
         SELECT pm.date
            FROM `payments` as pm
        )
    ORDER BY date

I think this is what you wanted,Both sales_report and payments need be considered as a table.then sort it.