Mysql 加入多个模型'；使用rails的子查询

我试图用最干净、最简单的方式在rails中编写以下查询

SELECT *
FROM 
    (SELECT DATE(logTime) as Date,
            SUM(CASE WHEN duration/60 <= 2 THEN 1 ELSE 0 END) AS d_0_2,
            SUM(CASE WHEN duration/60 > 2 AND duration/60 <=5 THEN 1 ELSE 0 END) AS d_2_5,
            SUM(CASE WHEN duration/60 > 5 AND duration/60 <= 10 THEN 1 ELSE 0 END) d_5_10,
            SUM(CASE WHEN duration/60 > 10 AND duration/60 <= 15 THEN 1 ELSE 0 END) d_10_15,
            SUM(CASE WHEN duration/60 > 15 THEN 1 ELSE 0 END) d_15_9999
    FROM session_logs
    WHERE DATE(logTime) > "2014-04-1" AND isClosed = 1
    GROUP BY DATE(logTime)) l1
LEFT JOIN
    (SELECT logDate AS Date, potential, conversion, bounce, newCustomers, repeatCustomers, averageTime
    FROM metrics
    WHERE client_id = 1 AND logDate BETWEEN "2014-01-01" AND "2015-05-04"
    GROUP BY logDate) l2 ON l1.date = l2.date

,

dwell=SessionLog。选择（“日期（logTime）”作为LogDate，
总和（如果持续时间/60 2和持续时间/60 5和持续时间/60 10和持续时间/60 15，则为1，否则为0结束）d_15_9999”）。
其中（“客户端id=？和isClosed=1，日期（日志时间）介于？和？之间，客户端id，开始日期，结束日期）

但是我想不出我应该如何加入那些有日期的集合

最好的办法是什么

谢谢

metric = Metric.select("potential,conversion,logDate,bounce,newCustomers,repeatCustomers,averageTime").
                where("client_id = ? and logDate between ? and ?",client_id,startDate,endDate)

dwell = SessionLog.select("DATE(logTime) as LogDate,
                                   SUM(CASE WHEN duration/60 <= 2 THEN 1 ELSE 0 END) AS d_0_2, 
                                   SUM(CASE WHEN duration/60 > 2 AND duration/60 <=5 THEN 1 ELSE 0 END) AS d_2_5,
                                   SUM(CASE WHEN duration/60 > 5 AND duration/60 <= 10 THEN 1 ELSE 0 END) d_5_10,
                                   SUM(CASE WHEN duration/60 > 10 AND duration/60 <= 15 THEN 1 ELSE 0 END) d_10_15,
                                   SUM(CASE WHEN duration/60 > 15 THEN 1 ELSE 0 END) d_15_9999").
                            where("client_id = ? AND isClosed = 1 AND DATE(logTime) between ? and ?", client_id, startDate, endDate)