MySQL組數由2列組成？

-1

鑑於一個payments表，其中包括payer_id和recipient_idMySQL組數由2列組成？

而計算收到的款項爲：

select COUNT(*) as payer_count, recipient_id 
FROM payments 
GROUP BY recipient_id 
ORDER BY payer_count DESC

如何計算：，用戶是支付的數目（用戶可以是payer_id或recipient_id）？

來源

2016-12-15 Blair Anderson

請解釋你的要求用簡單的英語。 'count（payer_id或recipient_id）'是無意義的語法。 – shmosel

您會得到一個固定ID，並且想要計算它顯示的付款行數？第一個是 – maraca

如果假設你要計算 - 每個人有一個特定的ID - 此人蔘與的付款交易次數，那麼工會應該全力幫助：

select person_id, count(*) 
from ((select payer_id as person_id from payments) union all (select recipient_id as person_id from payments)) paymentsOfPerson 
group by person_id 
order by person_id DESC

如果支付還可以包含的記錄payer_id = recipient_id（從一個賬戶轉移到同一個人的另一個帳戶），然後一個人在那裏照顧這類轉讓不計算兩次：

select person_id, count(*) 
from ((select payer_id as person_id from payments where payer_id != recepient_id) union all (select recipient_id as person_id from payments)) paymentsOfPerson 
group by person_id 
order by person_id DESC

來源

2016-12-15 22:46:55

！ '聯合'ftw –

一種方法是UNION ALL聚合前：

select id, count(*) as cnt, sum(recipient) as recipient_cnt, 
     sum(payer) as payer_cnt 
from ((select recipient_id as id, 1 as recipient, 0 as payer 
     from payments 
    ) union all 
     (select payer_id, 0, 1 
     from payments 
    ) 
    ) i 
group by id;

來源

2016-12-15 22:27:52

我認爲這可以解決你的問題：

SELECT COUNT(*) as payments_count 
    , COUNT(DISTINCT payer_id) distinct_payers 
    , recipient_id 
FROM payments 
GROUP BY recipient_id 
ORDER BY payer_count DESC

來源

2016-12-15 22:42:42 Pastor

MySQL組數由2列組成？

回答

相關問題