连接表仅产生一行

Question

i am trying to join the following two tables:

       Table Patient                   |        Table incident
patient.id   patient.birthdate         |  incident.patientid       serviceid
1                  1/1/2000            |       1                        8
2                  1/1/1990            |       1                        8
3                  1/1/2005            |       2                        10
4                  1/1/1980            |       3                        11
5                  1/1/2000            |       3                        11
6                  1/1/1990            |       3                        11
7                  1/1/1980            |       6                        23
8                  1/1/2000            |       7                        8

in order to make an age seperation of all patients grouped by their serviceid.

SELECT serviceid,
        SUM(CASE WHEN FLOOR((CAST (GetDate() AS INTEGER) - CAST(patient.birthdate AS INTEGER)) /365.25 ) BETWEEN 0 AND 15 THEN 1 ELSE 0 END) AS [Under 15],
        SUM(CASE WHEN FLOOR((CAST (GetDate() AS INTEGER) - CAST(patient.birthdate AS INTEGER)) /365.25 ) BETWEEN 16 AND 18 THEN 1 ELSE 0 END) AS [16-18],
        SUM(CASE WHEN FLOOR((CAST (GetDate() AS INTEGER) - CAST(patient.birthdate AS INTEGER)) /365.25 ) BETWEEN 19 AND 23 THEN 1 ELSE 0 END) AS [19-23],
        SUM(CASE WHEN FLOOR((CAST (GetDate() AS INTEGER) - CAST(patient.birthdate AS INTEGER)) /365.25 ) BETWEEN 24 AND 30 THEN 1 ELSE 0 END) AS [24-30],
        SUM(CASE WHEN FLOOR((CAST (GetDate() AS INTEGER) - CAST(patient.birthdate AS INTEGER)) /365.25 ) BETWEEN 31 AND 40 THEN 1 ELSE 0 END) AS [31-40],
        SUM(CASE WHEN FLOOR((CAST (GetDate() AS INTEGER) - CAST(patient.birthdate AS INTEGER)) /365.25 ) BETWEEN 41 AND 50 THEN 1 ELSE 0 END) AS [41-50],
        SUM(CASE WHEN FLOOR((CAST (GetDate() AS INTEGER) - CAST(patient.birthdate AS INTEGER)) /365.25 ) BETWEEN 51 AND 65 THEN 1 ELSE 0 END) AS [51-65],
        SUM(CASE WHEN FLOOR((CAST (GetDate() AS INTEGER) - CAST(patient.birthdate AS INTEGER)) /365.25 ) > 65 THEN 1 ELSE 0 END) AS [>65]

from patient
inner join incident
on patient.id = incident.patientConcerned
group by serviceid

But what i am trying above, counts the age of all patients for ALL their incidents, meaning that i am not counting distinct patients. (for example i am counting patient 1, twice and patient 3, three times)

So i want to join these two tables, but only with one row.

How can i do that?

Answer 1

Use Distinct operator. you query should be like following:

   SELECT Distinct a.id, a.birthdate ,b.patient from
   patient a inner join incident b ON a.serviceid=b.serviceid

Answer 2

Instead of sum() use count(distinct) . Here is an example:

SELECT serviceid,
       COUNT(DISTINCT CASE WHEN FLOOR((CAST (GetDate() AS INTEGER) - CAST(patient.birthdate AS INTEGER)) /365.25 ) BETWEEN 0 AND 15
                           THEN Patient.Id 
                      END) AS [Under 15],
       . . .

Answer 3

而不是group by serviceid group by patient.patient_id而是group by serviceid group by patient.patient_id