Question
Ahmad Bukhtiar · Nov 29, 2020

create join query on the same table

Hi 

I have a table where i want to create join query like

(select * from patients where facility=abc) qry1

left join (select * from patients where facility=xyz) qry2 on qry1.patientid = qry2.patientid

Product version:
IRIS 2020.1
00
1 0 3 81

Replies

There might be an easier way:

Select * from HS_Registry.Patient where Facility='ABC' and MPIID in

(select MPIID from HS_Registry.Patient where Facility='XYZ')

MPIID is an indexed field so this should be relatively fast. Since the Patent table is the same you really need to get your "*" data only once; you just need to constrain it to only return a subset of patients that have instances of both Facilities (if I understand you correctly)

thanks can i also use not in like below

Select * from HS_Registry.Patient where Facility='ABC' and MPIID NOT IN

(select MPIID from HS_Registry.Patient where Facility='XYZ')

Yes or course... in this case, you would return patients that have an instance of one Facility but not the other.