I have a query defined which needs to calculate averages for differtent parts of a questionnaire. There are now 1000 records in for testing, but the real db contains over 40000 already.
My sql statement now takes like minutes to load for only those 1000 records.
Does anyone have any tips on simplifying the sql statement.
QuestionnaireOffline contains the results from the query with also CodePostal, the table CodePostal contains the province. I need to get overview of the responses per province.
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I'm missing some kind of a DISTINCT in this picture. The total is way too high.
I have 5 different provinces. If i ran this query on my data then the total amount is way higher than the no of records I have.
I must say, If i sum all the results I get the same number of records as I have when I query (without DISTINCT) in a wrongly way like this:
pmelkebeke,
It would be useful to see some sample data. EE now allows you to directly upload
files to your question.
Please be advised that once you upload a file, it can be publicly accessed, and that it
may not be possible to fully and permanently delete it. Therefore, be very careful about
posting proprietary, confidential, or other sensitive information. If necessary, use "fake"
and/or obfuscated data in your sample.
Regards,
Patrick
This query
SELECT * FROM QUESTIONNAIREOFFLINE, Codespostal WHERE Codepostal = CP
may not work as you expect. You will get a 'CARTESIAN JOIN' between the two tables. It should read:
SELECT QUESTIONNAIREOFFLINE.* FROM QUESTIONNAIREOFFLINE JOIN Codespostal on QUESTIONNAIREOFFLINE.CodeP
This seems to be working against the sample data:
SELECT Count(*) AS nTotal, Sum(IIf(q.Mode = "Papier", 1, 0)) AS nPapier, Sum(IIf(q.Mode = "Internet", 1, 0)) AS nInternet
FROM QuestionnaireOffline q INNER JOIN
(SELECT c.CP, Max(c.Province) AS Prov FROM CodesPostal c GROUP BY c.CP) cc ON q.CodePostal = cc.CP
WHERE cc.Prov = "BRABANT WALLON";
Business Accounts
Answer for Membership
by: matthewspatrickPosted on 2008-10-24 at 03:44:38ID: 22794871
SELECT Count(q.CodePostal) AS nTotal, Sum(IIf(q.mode = "Papier", 1, 0) AS nPapier,
Sum(IIf(q.mode = "Internet", 1, 0) AS nInternet, ...
FROM QuestionnaireOffline q INNER JOIN
CodesPostal c ON q.CodePostal = c.CP
WHERE c.Province = "BRABANT WALLON"