如何在一段时间（6周）内发现3次或多次事件？

Question

我需要根据诊所访问情况建立患者人群。此人群的资格标准（筛选）是在评估年的6周内进行3次访问。我如何编码？

Answer 1

DECLARE @Records TABLE (ptID INT, date DATE) 

INSERT INTO @Records VALUES 
    (1, '2016-01-01') 
    ,(1, '2016-01-05') 
    ,(1, '2016-02-01') 
    ,(1, '2016-10-01') 
    ,(2, '2015-12-01') 
    ,(2, '2015-12-10') 
    ,(2, '2015-12-31') 
    ,(2, '2016-01-01') 
    ,(2, '2016-01-05') 
    ,(2, '2016-03-05') 
    ,(3, '2016-01-01') 
    ,(3, '2016-02-01') 
    ,(3, '2016-03-01') 
    ,(3, '2016-04-01') 
    ,(3, '2016-05-01') 
    ,(3, '2016-06-01') 
    ,(3, '2016-07-01') 
    ,(3, '2016-08-01') 
select a.ptID , a.date 
from @Records a 
join @Records b 
     on a.ptID = b.ptID 
    and datediff(wk, a.date, b.date) <= 6 
    and datediff(wk, a.date, b.date) > 0 
    and DATEPART(yy, a.date) = DATEPART(yy, b.date) 
group by a.ptID, a.date 
having count(*) >= 2 

Answer 2

狗仔队值得将表与自身进行比较的所有功劳。我只是在这里改进他的比较。

DECLARE @Records TABLE (
    PatientID  INT 
    ,VisitDate  DATE 
    ) 

INSERT INTO @Records VALUES 
    (1, '2016-01-01') 
    ,(1, '2016-01-05') 
    ,(1, '2016-02-01') 
    ,(1, '2016-10-01') 
    ,(2, '2015-12-01') 
    ,(2, '2016-01-01') 
    ,(2, '2016-01-05') 
    ,(2, '2016-03-05') 

;WITH SixWeeks 
    AS (
     SELECT a.PatientID AS PID1, a.VisitDate AS Date1, 
       b.PatientID AS PID2, b.VisitDate AS Date2, 
       DATEDIFF(dd, a.VisitDate, b.VisitDate) AS DD 
      FROM @Records a 
       JOIN @Records b 
        ON a.PatientID = b.PatientID 
         AND DATEDIFF(dd, a.VisitDate, b.VisitDate) <= 42 
         AND DATEPART(yy,a.VisitDate) = '2016' 
      WHERE EXISTS (SELECT * FROM @Records WHERE (VisitDate > a.VisitDate AND VisitDate < b.VisitDate)) 
     ) 

SELECT PID1 FROM SixWeeks 
    GROUP BY PID1