***抱歉，我只是根据查询提供了正确的数据。
我正在根据录取日期寻找再入院资格。任何具有允许日期的ptID，在前一个允许日期的30天内按遭遇分组。每次遭遇需要最低允许日期。我们可以根据下面的数据说明四月份。像这样的许多问题，但他们没有多个遭遇ID。我也知道日期作为参数存在问题。
我的表格中有以下数据;
encounter PtID admit discharge
------------------------------------------------------------------
V00018357259 M00104410 4/12/17 8:36 AM NULL
V00018357259 M00104410 4/12/17 8:36 AM 4/12/17 1:55 PM
V00018362040 M00104410 4/13/17 4:38 PM NULL
V00018362040 M00104410 4/13/17 5:49 PM NULL
V00018362040 M00104410 4/13/17 11:04 PM 4/13/17 6:01 PM
V00018362040 M00104410 4/13/17 11:04 PM 4/14/17 11:30 AM
V00018408554 M00104410 5/3/17 9:51 AM NULL
V00018406101 M00104410 5/3/17 10:12 AM NULL
希望收到以下内容作为输出：
EncounterID PtID Admit Readmission DaySpan
-----------------------------------------------------------------------
V00018357259 M00104410 4/12/17 8:36 AM 4/13/17 4:38 PM 1
V00018357259 M00104410 4/12/17 8:36 AM 5/3/17 9:51 AM 21
V00018357259 M00104410 4/12/17 8:36 AM 5/3/17 10:12 AM 21
V00018362040 M00104410 4/13/17 4:38 PM 5/3/17 9:51 AM 20
V00018362040 M00104410 4/13/17 4:38 PM 5/3/17 10:12 AM 20
V00018408554 M00104410 5/3/17 9:51 AM 5/3/17 10:12 AM 0
我有当前的查询
select
av.patient_id,
av.encounter,
av.admit_date,
av1.admit_date as readmission,
datediff(d, av.admit_date, av1.admit_date) as dayspan
from
adt_visit av
left join
adt_visit av1 on av1.patient_id = av.patient_id
where
(datediff(d, av.admit_date, av1.admit_date) > 0)
and (datediff(d, av.admit_date, av1.admit_date) <= 30)
and av.admit_date >'4/1/2017' and av.admit_date < '4/30/2017'
and av.patient_id = 'M00104410'
group by
av.patient_id
,av.encounter
, av.admit_date
, av1.admit_date
产生这个：
PtID Encounter Admit Readmission Dayspan
------------------------------------------------------------------------
M00104410 V00018357259 4/12/17 8:36 AM 4/13/17 4:38 PM 1
M00104410 V00018357259 4/12/17 8:36 AM 4/13/17 5:49 PM 1
M00104410 V00018357259 4/12/17 8:36 AM 4/13/17 11:04 PM 1
M00104410 V00018357259 4/12/17 8:36 AM 5/3/17 9:51 AM 21
M00104410 V00018357259 4/12/17 8:36 AM 5/3/17 10:12 AM 21
M00104410 V00018362040 4/13/17 4:38 PM 5/3/17 9:51 AM 20
M00104410 V00018362040 4/13/17 4:38 PM 5/3/17 10:12 AM 20
有人可以帮忙吗？谢谢！