select count(distinct q2.device_id,q2.date)/count(distinct q1.device_id,q1.date) avg_ret from question_practice_detail q1 left join _牛客网_牛客在手,offer不愁
select count(distinct q2.device_id,q2.date)/count(distinct q1.device_id,q1.date) as avg_ret from question_practice_detail as q1 left outer join questi_牛客网_牛客在手,offer不愁
SELECT COUNT(q2.device_id) / COUNT(q1.device_id) AS avg_ret FROM (SELECT DISTINCT device_id, date FROM question_practice_detail)as q1 LEFT JOI_牛客网_牛客在手,offer不愁
select count(distinct q1.device_id)/count(distinct q2.device_id) as again_rate from question_practice_detail q1 left join question_practice_detail q2 on q1.device_id=q2.device_id and q1.date=date_add(q2.date,interval 1 day); 请教:为什么这么写算不出来呢 ...
SELECT COUNT(DISTINCT(CONCAT(a.device_id, ' ', a.date)))/COUNT(DISTINCT CONCAT(b.device_id, ' ', b.date)) AS avg_ret FROM ( SELECT q1.device_id, q1.date FROM question_practice_detail AS q1 INNER JOIN question_practice_detail AS q2 ON q1.device_id = q2.device_id AND DATE_ADD...
select count(q2.device_id)/count(q1.device_id) as avg_ret from (select distinct device_id,date from question_practice_detail)q1 left join (select distinct device_id,date from question_practice_detail)q2 on q1.device_id=q2.device_id and q2.date=date_add(q1.date,interval 1 day) ...