How to add inner join to query with multiple joins?

Question

I'm trying to add an inner join to query that was done by someone else, but I keep getting errors; I'm trying to figure out the correct way to add it, the inner join to be added is:

select 
    pa.AdmissionID, pad.AdmissionID, pad.AdmTypeID
from 
    v_dbPatientAdmissions pa
inner join 
    V_DbPatientAdmissionAddition pad on pad.AdmissionID = pa.AdmissionID
where 
    pad.AdmTypeID in (3, 37, 42, 43, 44, 51)

And the query I'm trying to add the inner join to is:

SELECT 
    PA.RegCode UHID, PA.Specialisation, A.CREATEDATE ADM_ORDER, 
    PA.CREATEDATE ADM_DATE,  
    (CAST((DATEDIFF(minute, A.CREATEDATE, PA.CREATEDATE))/60 AS VARCHAR)+' H:'                                 
        + CAST((DATEDIFF(minute,A.CREATEDATE, PA.CREATEDATE))%60 AS VARCHAR)+' M') AS DURATION
FROM 
    (SELECT 
         M.IPID, M.PatientID, A.CREATEDATE 
     FROM 
         v_dbPatientAdvice A
     INNER JOIN 
         v_dbPatientMonitoring M ON M.MonitorID = A.MonitorID
     WHERE 
         A.FollowUpType = 2) A 
INNER JOIN  
    (SELECT 
         PA.PatientID, PA.CREATEDATE, PA.RegCode, S.Specialisation, PA.PatientType
     FROM 
         v_dbPatientAdmissions PA
     INNER JOIN 
         v_dbSpecializations S ON S.SpecialiseID = PA.SpecialiseID) PA ON A.PatientID = PA.PatientID
                                                                       AND PA.PatientType = 2
                                                                       AND PA.CREATEDATE > A.CREATEDATE
                                                                       AND PA.CREATEDATE < DATEADD(DAY, 1, A.CREATEDATE)
WHERE 
    A.CREATEDATE > '2017-01-01'
    AND A.CREATEDATE < DATEADD(DAY, 1, '2018-09-20')

The inner join to be added has one new table V_DbPatientAdmissionAddition the other table is already in the query v_dbPatientAdmissions.

I've tried adding it as a subquery and also tried adding it without the From v_dbPatientAdmissions but still there is something wrong with the syntax.

If someone could help in how I can add the inner join to the query that would be helpful! I hope I was able to explain the issue clearly.

Answer 1

You can extend the 2nd subquery. You'll need to also extend the main SELECT with the new columns that you want to be returned.

SELECT PA.RegCode UHID, PA.Specialisation, A.CREATEDATE ADM_ORDER, PA.CREATEDATE ADM_DATE,  
(CAST((DATEDIFF(minute, A.CREATEDATE, PA.CREATEDATE))/60 AS VARCHAR)+' H:'                                 
+ CAST((DATEDIFF(minute,A.CREATEDATE, PA.CREATEDATE))%60 AS VARCHAR)+' M') AS DURATION
FROM (SELECT M.IPID, M.PatientID, A.CREATEDATE 
      FROM v_dbPatientAdvice A
      INNER JOIN v_dbPatientMonitoring M ON M.MonitorID = A.MonitorID
      WHERE A.FollowUpType = 2
) A 
INNER JOIN (SELECT PA.PatientID, PA.CREATEDATE, PA.RegCode, S.Specialisation, PA.PatientType,
                   PA.AdmissionID, pad.AdmissionID, pad.AdmTypeID -- New SELECT columns
            FROM v_dbPatientAdmissions PA
            INNER JOIN v_dbSpecializations S ON S.SpecialiseID = PA.SpecialiseID
            INNER JOIN V_DbPatientAdmissionAddition pad on pad.AdmissionID=pa.AdmissionID -- New JOIN
            WHERE pad.AdmTypeID in (3,37,42,43,44,51) -- new WHERE
) PA ON A.PatientID = PA.PatientID
    AND PA.PatientType = 2
    AND PA.CREATEDATE > A.CREATEDATE
    AND PA.CREATEDATE < DATEADD(DAY, 1, A.CREATEDATE)
WHERE A.CREATEDATE > '2017-01-01'
AND   A.CREATEDATE < DATEADD(DAY, 1, '2018-09-20')

Answer 2

You can use a CTE to simplify this work:

with cte as (
      select pa.AdmissionID, pad.AdmissionID,pad.AdmTypeID
      from v_dbPatientAdmissions pa inner join
           V_DbPatientAdmissionAddition pad on pad.AdmissionID=pa.AdmissionID
      where pad.AdmTypeID in (3, 37, 42, 43, 44, 51)
    )
select . . .
from . . . join
     newtable nt
     on ?.? = nt.?  -- whatever the `join` conditions are
. . .