Subject Re: [firebird-support] How do I return an accurate COUNT(*) when a JOIN is involved?
Author Martijn Tonies (Upscene Productions)
Post date 2014-10-13T18:56:23Z
Hello Mike,
 
In the second query, you’re counting records and then do the DISTINCT, so the
result is 32, and if you “distinct” that result, there’s only 1 record, with a value
of 32.
 
What you seem to want, is to COUNT(DISTINCT(...))
 
With regards,

Martijn Tonies
Upscene Productions
http://www.upscene.com

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Sent: Monday, October 13, 2014 8:50 PM
Subject: [firebird-support] How do I return an accurate COUNT(*) when a JOIN is involved?
 

Greetings All,
 
Firebird 1.5.3 (Yes I know it is old)
 
Using the following syntax with 09/01/14 and 09/04/14 for the parameters fetches 20 distinct records
 
      SELECT DISTINCT DCD.ACCT_ID, AC.CLT_ID
                 FROM DEBTOR_CASE_DEBT DCD
                 JOIN ACCT_CASE AC ON AC.ACCT_ID = DCD.ACCT_ID
                  AND AC.CASE_ID = DCD.CASE_ID
                WHERE DCD.STATUS_DATE BETWEEN :V_BEGIN_DATE AND :V_END_DATE
                  AND DCD.STATUS_CODE = 'B'
Using this syntax with 09/01/14 and 09/04/14 for the parameters fetches a count of 32
 
      SELECT DISTINCT COUNT(DCD.PERSON_ID)
                 FROM DEBTOR_CASE_DEBT DCD
                 JOIN ACCT_CASE AC ON AC.ACCT_ID = DCD.ACCT_ID
                  AND AC.CASE_ID = DCD.CASE_ID
                WHERE DCD.STATUS_DATE BETWEEN :V_BEGIN_DATE AND :V_END_DATE
                  AND DCD.STATUS_CODE = 'B'
 
How do I accurately return the correct count using the COUNT() function?  In this case it should beturn 20 not 32
 
Any ideas appreciated.
 
Thanks,
Mike