SQL Joining 6 Tables
Solution 1:
Since appointmnent_id
is the primary key of Appointment
, this table has a 1:N
relationship with all 6 tables.
This is the case where joining to these 6 tables will produce multiple rows with duplicate data, it's like a Cartesian Product
. For example if (for only one id=46
), there are:
- 3 rows for
PatientInvestigation
- 6 rows for
PatientTreatmentMedicine
- 4 rows for
PatientFindings
- 2 rows for
PatientDiagnosis
- 2 rows for
PatientCC
- 5 rows for
PatientAdvice
you'll get 3x6x4x2x2x5 = 1440
rows in the result set, while you only need 3+6+4+2+2+5 (+1) = 23
rows. That is 60 times more rows (and with many more columns) than needed.
It's better if you do 6 separate queries with one JOIN to one (of the 6) tables in each query (and one more query to get the data from the base table Appointment
). And combine the results of the 6 queries in the application code. Example for the base query and the query to join to the first table:
Base table:
SELECT
a.appointment_id,
a.patient_id
FROM
Appointment AS a
WHERE
a.appointment_id = 46
Join-1 to PatientInvestigation:
SELECT
pi.investigation_name,
pi.investigation_id
FROM
Appointment AS a
JOIN
PatientInvestigation AS pi
ON pi.appointment_id = a.appointment_id
WHERE
a.appointment_id = 46
Solution 2:
SELECT
Appointment.appointment_id,
Appointment.patient_id,
PatientInvestigaiton.investigation_name,
PatientInvestigaiton.investigation_id,
PatientTreatmentMedicine.medecine_id,
PatientTreatmentMedicine.medicinename,
PatientTreatmentMedicine.medicinetype,
PatientFindings.finding_id,
PatientFindings.finding_value,
PatientAdvice.advice_description,
PatientCC.cc_value,
PatientCC.cc_id,
PatientDiagonosis.diagonosis_name,
PatientDiagonosis.diagonosis_id
FROM
Appointment
LEFT OUTER JOIN PatientInvestigaiton ON Appointment.appointment_id = PatientInvestigaiton.appointment_id AND Appointment.appointment_id='46'
LEFT OUTER JOIN PatientTreatmentMedicine ON Appointment.appointment_id = PatientTreatmentMedicine.appointment_id
LEFT OUTER JOIN PatientFindings ON Appointment.appointment_id = PatientFindings.appointment_id
LEFT OUTER JOIN PatientDiagonosis ON Appointment.appointment_id = PatientDiagonosis.appointment_id
LEFT OUTER JOIN PatientCC ON Appointment.appointment_id = PatientCC.appointment_id
LEFT OUTER JOIN PatientAdvice ON Appointment.appointment_id = PatientAdvice.appointment_id
Solution 3:
SELECT {TABLE1}.appointment_id,{OTHER FIELDS} FROM {TABLE1}
JOIN {TABLE2} ON {TABLE1}.appointment_id = {TABLE2}.appointment_id
JOIN {TABLE3} ON {TABLE1}.appointment_id = {TABLE3}.appointment_id
JOIN {TABLE4} ON {TABLE1}.appointment_id = {TABLE4}.appointment_id
JOIN {TABLE5} ON {TABLE1}.appointment_id = {TABLE5}.appointment_id
JOIN {TABLE6} ON {TABLE1}.appointment_id = {TABLE6}.appointment_id
JOIN {TABLE7} ON {TABLE1}.appointment_id = {TABLE7}.appointment_id
JOIN {TABLE8} ON {TABLE1}.appointment_id = {TABLE8}.appointment_id;
Try this:
SELECT
dbo.Appointment.appointment_id, dbo.Appointment.patient_id,
dbo.PatientInvestigaiton.investigation_name, dbo.PatientInvestigaiton.investigation_id,
dbo.PatientTreatmentMedicine.medecine_id, dbo.PatientTreatmentMedicine.medicinename, dbo.PatientTreatmentMedicine.medicinetype,
dbo.PatientFindings.finding_id, dbo.PatientFindings.finding_value,
dbo.PatientAdvice.advice_description,
dbo.PatientCC.cc_value, dbo.PatientCC.cc_id,
dbo.PatientDiagonosis.diagonosis_name, dbo.PatientDiagonosis.diagonosis_id
FROM
dbo.Appointment
LEFT JOIN dbo.PatientInvestigaiton
ON dbo.Appointment.appointment_id = dbo.PatientInvestigaiton.appointment_id
LEFT JOIN dbo.PatientTreatmentMedicine
ON dbo.Appointment.appointment_id = dbo.PatientTreatmentMedicine.appointment_id
LEFT JOIN dbo.PatientFindings
ON dbo.Appointment.appointment_id = dbo.PatientFindings.appointment_id
LEFT JOIN dbo.PatientDiagonosis
ON dbo.Appointment.appointment_id = dbo.PatientDiagonosis.appointment_id
LEFT JOIN dbo.PatientCC
ON dbo.Appointment.appointment_id = dbo.PatientCC.appointment_id
LEFT JOIN dbo.PatientAdvice
ON dbo.Appointment.appointment_id = dbo.PatientAdvice.appointment_id
WHERE
dbo.Appointment.appointment_id='46';
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