Issues with duplicated Ids in aggregated subquery - mysql

Question

I have this query: (apologies for complexity, I'm not certain what I can remove without impacting the question)
SELECT COUNT(*) AS total,
SUM(o.total) AS total_loss,
SUM((SELECT SUM(cost_price) FROM `orders_items` WHERE orders_id = o.orders_id)) AS cost_total ,
SUM((SELECT COUNT(*) FROM refunds AS r1 WHERE r1.order_id = r.order_id AND NOT r.reason IS NULL)) AS refund_count ,
SUM((SELECT COUNT(*) FROM exchanges AS e1 WHERE e1.order_id = e.order_id AND e.type = :countResend AND NOT e.reason IS NULL)) AS resend_count ,
SUM((SELECT COUNT(*) FROM exchanges AS e2 WHERE e2.order_id = e.order_id AND e.type = :countExchange AND NOT e.reason IS NULL)) AS exchange_count
FROM orders AS o
JOIN sales_channel_config AS s ON o.sales_channel = s.sales_channel AND o.sub_sales_channel = s.sub_sales_channel
JOIN courier_service AS cs ON o.courier_service = cs.code
LEFT JOIN refunds AS r ON o.orders_id = r.order_id
JOIN orders_items AS oi ON o.orders_id = oi.orders_id
JOIN third_party_config AS tc ON SUBSTRING(oi.product_id_new, 3, 2) = tc.code
LEFT JOIN exchanges AS e ON o.orders_id = e.order_id
WHERE 1 = 1
AND o.tracking_num NOT IN (:cancelStatus)
AND (o.order_date >= :startDate AND o.order_date <= :endDate)
AND o.courier_service = :courier
AND SUBSTRING(oi.product_id_new, 3, 2) = :supplier
AND (NOT r.reason IS NULL OR NOT e.reason IS NULL)
The problem I'm having is that the various SUM((query)) clauses are counting duplicate orders, which is proving difficult to resolve. For example:
SUM((SELECT COUNT(DISTINCT r1.order_id) FROM refunds AS r1 WHERE r1.order_id = r.order_id AND NOT r.reason IS NULL)) AS refund_count ,
And
SUM((SELECT COUNT(*) FROM refunds AS r1 WHERE r1.order_id = r.order_id AND NOT r.reason IS NULL GROUP BY r1.order_id)) AS refund_count ,
Do not lower the resulting SUM at all. I have confirmed that the data returned will contain duplicates via another structurally identical query that returns rows from the parent query. When the other query is run without duplicate filtering, the counts match correctly so I'm confident that my problem query is accurate aside from including duplicated order ids.
So can anyone suggest another approach I might try?

Answer 1

For anyone who might benefit:
I removed most of the select logic and grouped on orders_id, which gives me an entirely accurate list of relevant orders:
SELECT o.orders_id AS order_id, r.id AS refund_id, e.id AS exchange_id, e.type AS exchange_type
FROM orders AS o
JOIN sales_channel_config AS s ON o.sales_channel = s.sales_channel AND o.sub_sales_channel = s.sub_sales_channel
JOIN courier_service AS cs ON o.courier_service = cs.code
LEFT JOIN refunds AS r ON o.orders_id = r.order_id
JOIN orders_items AS oi ON o.orders_id = oi.orders_id
JOIN third_party_config AS tc ON SUBSTRING(oi.product_id_new, 3, 2) = tc.code
LEFT JOIN exchanges AS e ON o.orders_id = e.order_id
WHERE 1 = 1
AND o.tracking_num NOT IN (:cancelStatus)
AND (o.order_date >= :startDate
AND o.order_date <= :endDate)
AND o.courier_service = :courier
AND SUBSTRING(oi.product_id_new, 3, 2) = :supplier
AND (NOT r.reason IS NULL OR NOT e.reason IS NULL)
GROUP BY (o.orders_id)
I've bitten the bullet here. I'm going to do some post processing to get the counts themselves, which is at least possible for me now.
Still don't understand why getting distinct values in the sub selects failed though.