基于最大最小日期的案例陈述

Question

我有Memnumber, activity type, activity date, activity ID列。一个成员可以在几天后开展活动。我想写一个案例陈述，如果活动日期最初是初始，那么如果活动是最近的那么MR，如果这两个日期之间有任何活动，那么BETWEEN。它们需要按Memnumber和治疗类型分组。

我写的查询为：

--MR County Tree
SELECT T0.MEMBERNUMBER,
    T0.ACTIVITYTYPE,
    T1.MR_CY17,
    T1.IN_CY17,
    T0.ACTIVITY_DATE,
    (T0.ACTIVITYID)
FROM DLA_EXTRACT_FINAL T0
INNER JOIN (
    SELECT MEMBERNUMBER,
        ACTIVITYTYPE,
        MAX(ACTIVITY_DATE) MR_CY17,
        MIN(ACTIVITY_DATE) IN_CY17
    FROM DLA20_EXTRACT_FINAL
    WHERE to_char(ACTIVITY_DATE, 'YYYYMMDD') >= 20170101
        AND to_char(ACTIVITY_DATE, 'YYYYMMDD') <= 20171231
    GROUP BY MEMBERNUMBER,
        ACTIVITYTYPE
    ) T1 ON T0.MEMBERNUMBER = T1.MEMBERNUMBER
    AND T0.ACTIVITYTYPE = T1.ACTIVITYTYPE
    AND T0.ACTIVITY_DATE = T1.MR_CY17
--where  T0.ACTIVITYTYPE='MT'
WHERE t0.MEMBERNUMBER = 'M500085268'
GROUP BY T0.MEMBERNUMBER,
    T0.ACTIVITYTYPE,
    T1.MR_CY17,
    T1.IN_CY17,
    T0.ACTIVITYID,
    T0.ACTIVITY_DATE
ORDER BY T0.MEMBERNUMBER,
    T0.ACTIVITYTYPE,
    T1.MR_CY17,
    T1.IN_CY17.

寻找解决方案。

Answer 1

您想使用窗口功能。类似的东西：

SELECT T0.MEMBERNUMBER,
    T0.ACTIVITYTYPE,
    T0.ACTIVITY_DATE,
    T0.ACTIVITYID,
    case when row_number() over (partition by T0.MEMBERNUMBER, T0.ACTIVITYTYPE
        order by T0.ACTIVITY_DATE) = 1 then 1 else 0 end most_initial,
    case when row_number() over (partition by T0.MEMBERNUMBER, T0.ACTIVITYTYPE
        order by T0.ACTIVITY_DATE desc) = 1 then 1 else 0 end most_recent
FROM DLA_EXTRACT_FINAL T0

然后，如果most_intial = 1，则可以使用case语句标记为INITIAL，如果most_recent = 1则使用MR标记，如果两者都为0，则使用BETWEEN。