在子查询中使用联接？

Question

The following query is returning all affiliate_id 's where the amount owed is more than 50.

        SELECT
            t1.affiliate_id
        FROM
        (
            SELECT affiliate_id, SUM(payout) AS payout_total
            FROM exp_cdwd_aff_purchases
            GROUP BY affiliate_id
        ) t1
        LEFT JOIN
        (
            SELECT affiliate_id, SUM(amount_paid) AS amount_paid_total
            FROM exp_cdwd_aff_payments
            GROUP BY affiliate_id
        ) t2
            ON t1.affiliate_id = t2.affiliate_id
        WHERE t1.payout_total > COALESCE(t2.amount_paid_total, 0) + 50

I need to also return an email address for each affiliate_id from the table exp_member_data . The affiliate_id can be referenced against member_id .

I had thought the following may work, but it doesn't. Can anyone explain how I can get this result?

        SELECT
            t1.affiliate_id, t1.m_field_id_26
        FROM
        (
            SELECT af.affiliate_id, SUM(af.payout) AS payout_total, md.m_field_id_26
            FROM exp_cdwd_aff_purchasesAS af
            LEFT JOIN exp_member_data AS md.member_id = af.affiliate_id
            GROUP BY affiliate_id
        ) t1
        LEFT JOIN
        (
            SELECT affiliate_id, SUM(amount_paid) AS amount_paid_total
            FROM exp_cdwd_aff_payments
            GROUP BY affiliate_id
        ) t2
            ON t1.affiliate_id = t2.affiliate_id
        WHERE t1.payout_total > COALESCE(t2.amount_paid_total, 0) + 50

Answer 1

If I read your query correctly, then the easiest thing to do would be to just add another join to the end to bring in the email address. Something like this:

SELECT
    t1.affiliate_id,
    COALESCE(t3.m_field_id_26, 'email is NA') AS m_field_id_26
FROM
(
    SELECT affiliate_id, SUM(payout) AS payout_total
    FROM exp_cdwd_aff_purchases
    GROUP BY affiliate_id
) t1
LEFT JOIN
(
    SELECT affiliate_id, SUM(amount_paid) AS amount_paid_total
    FROM exp_cdwd_aff_payments
    GROUP BY affiliate_id
) t2
    ON t1.affiliate_id = t2.affiliate_id
LEFT JOIN exp_member_data t3
    ON t1.affiliate_id = t3.member_id
WHERE t1.payout_total > COALESCE(t2.amount_paid_total, 0) + 50

Doing the join inside your aggregation query, as you currently have it, probably isn't ideal because that subquery exists to tally things, not to include email address information.