Mysql SQL：计算刚刚结转的计数列

好的，我能不能在使用COUNT&的同一个查询中对列进行数学运算？下面是错误消息

“#1064-您的SQL语法有错误；请检查以下手册： 对应于您的MySQL服务器版本，以便使用正确的语法 近“不同的付款。客户id）作为Jan_retain_cust， Jan_将客户/1533保留为3号线的CAC”

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您缺少一个

group by

子句。此外，您试图在同一个select中的表达式中使用别名

Jan\u retain\u cust

，这是不允许的。只需将别名

Jan\u retain\u cust

替换为原始表达式，即

COUNT（DISTINCT payments.customer\u id）

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您不能在同一查询中引用别名列

select January.customer_id as Jancust_id,
    COUNT(distinct January.customer_id) as Jan_orig_cust,
    COUNT(distinct payments.customer_id) as Jan_retain_cust,
    COUNT(distinct payments.customer_id) / 1533 as CAC_referral
from January_Cohort January
left join telemon_payments_data payments on January.customer_id = payments.customer_id
where January.acquisition_source = 'referral'
    and payments.payment_date between '2016-06-01' and '2016-06-31'
group by January.customer_id;

选择一月。客户id作为Jancust\u id，
将（不同的1月份客户id）计算为1月份原始客户，
将（不同的付款。客户id）计算为1月1日保留客户，
Jan_retain_cust/1533作为CAC_推荐，谢谢，所以这就是我上面提到的
select January.customer_id as Jancust_id,
    COUNT(distinct January.customer_id) as Jan_orig_cust,
    COUNT(distinct payments.customer_id) as Jan_retain_cust,
    COUNT(distinct payments.customer_id) / 1533 as CAC_referral
from January_Cohort January
left join telemon_payments_data payments on January.customer_id = payments.customer_id
where January.acquisition_source = 'referral'
    and payments.payment_date between '2016-06-01' and '2016-06-31'
group by January.customer_id;

SELECT January.customer_id AS Jancust_id, 
COUNT( DISTINCT January.customer_id ) AS Jan_orig_cust,
COUNT (DISTINCT payments.customer_id) as Jan_retain_cust,
Jan_retain_cust/ 1533 AS CAC_referral    <--- You can not do.
FROM January_Cohort January
LEFT JOIN telemon_payments_data payments
ON January.customer_id = payments.customer_id
WHERE January.acquisition_source = 'referral'
AND 
payments.payment_date BETWEEN '2016-06-01' and '2016-06-31'