Question

I need to intersect two tables based
on a column,in both tables.

Here’s my code snippet :

SELECT b.VisitID,  b.CarrierName, b.PhoneNum, b.PatientName, b.SubscriberID, b.SubscriberName, 
        b.ChartNum, b.DoB, b.SubscriberEmp, b.ServiceDate, b.ProviderName, b.CPTCode, b.AgingDate, 
        b.BalanceAmt, f.FollowUpNote, f.InternalStatusCode FROM billing b JOIN followup f 
        USING (VisitID) WHERE b.VisitID = f.VisitID

In the ‘followup’ table I’ve 281 rows AND ‘billing’ table contains 2098 rows. When I execute this query I’m getting 481 rows.

Did anyone faces this sort of problem?
Could you help me to INTERSECT these tables?

Thanx in advance..

Answer 1

I think you like to do a left join here (not an inner join as in your example):

SELECT b.VisitID,  b.CarrierName, b.PhoneNum, b.PatientName,
  b.SubscriberID, b.SubscriberName, b.ChartNum, b.DoB,
  b.SubscriberEmp, b.ServiceDate, b.ProviderName, b.CPTCode,
  b.AgingDate, b.BalanceAmt,
  f.FollowUpNote, f.InternalStatusCode
FROM billing b
LEFT JOIN followup f ON b.VisitID = f.VisitID

This will also return rows from the ‘billing’ table that don’t have corresponding fields in the ‘followup’ table.