SELECT mcategory CAST AVGTIMESTAMPDIFFSECOND atime dtime AS UNSIGNED AS median_decision_time FROM app a JOIN mapping_table m ON apackage_name = mpackage_name JOIN SELECT userid package_name MINtime

-- 从app表中选择所有行，并与mapping_table表中的行进行连接，以便获取应用程序的类别信息 SELECT m.category, -- 计算决策时间的中位数，并将结果转换为无符号整数 CAST( AVG(TIMESTAMPDIFF(SECOND, a.time, d.time)) AS UNSIGNED ) AS median_decision_time -- 从app表中选择所有行，并与下载操作类型相应的行进行连接，以便获取每个用户和应用程序的第一次下载时间 FROM app a JOIN mapping_table m ON a.package_name = m.package_name JOIN ( -- 从app表中选择所有行，并按用户ID和应用程序名称分组，以获取每个用户和应用程序的第一次下载时间 SELECT userid, package_name, MIN(time) AS time FROM app WHERE action_type = 'download' GROUP BY userid, package_name ) AS d ON a.userid = d.userid AND a.package_name = d.package_name -- 从app表中选择所有行，并与itemShow操作类型相应的行进行连接，以便获取每个类别的应用程序的中位数决策时间 WHERE a.action_type = 'itemShow' GROUP BY m.category。