MySQL组数由2列组成？

-1

鉴于一个payments表，其中包括payer_id和recipient_idMySQL组数由2列组成？

而计算收到的款项为：

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

如何计算：，用户是支付的数目（用户可以是payer_id或recipient_id）？

来源

2016-12-15 Blair Anderson

请解释你的要求用简单的英语。 'count（payer_id或recipient_id）'是无意义的语法。 – shmosel

您会得到一个固定ID，并且想要计算它显示的付款行数？第一个是 – maraca

如果假设你要计算 - 每个人有一个特定的ID - 此人参与的付款交易次数，那么工会应该全力帮助：

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

如果支付还可以包含的记录payer_id = recipient_id（从一个账户转移到同一个人的另一个帐户），然后一个人在那里照顾这类转让不计算两次：

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

来源

2016-12-15 22:46:55

！ '联合'ftw –

一种方法是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;

来源

2016-12-15 22:27:52

我认为这可以解决你的问题：

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

来源

2016-12-15 22:42:42 Pastor

MySQL组数由2列组成？

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