I have a MySQL query that outputs to a php table but I'm having issues in joining two tables that both use a COUNT:
$query = "SELECT mqe.registration,
COUNT(*) AS numberofenqs,
COUNT(DISTINCT ucv.ip) AS unique_views,
SUM(ucv.views) AS total_views
FROM main_quick_enquiries AS mqe
LEFT OUTER JOIN used_car_views AS ucv
ON ucv.numberplate = mqe.registration
WHERE mqe.registration IS NOT NULL
GROUP BY mqe.registration ORDER BY numberofenqs DESC";
The query runs, but the number within the numberofenqs column is always wrong as i know from performing that query on its own that it comes in with the correct result:
SELECT registration, COUNT(*) AS numberofenqs FROM main_quick_enquiries GROUP BY registration ORDER BY numberofenqs DESC
Why is the COUNT(*) not working correctly in top query code and where is it getting the figures from?
it could be because of LEFT OUTER JOIN ...
Try to run this:
SELECT registration
, count(*)
FROM main_quick_enquiries
GROUP BY registration
and compare it with this result
SELECT mqe.registration
, count(*)
FROM main_quick_enquiries mqe
LEFT OUTER JOIN used_car_views ucv
ON ucv.numberplate = mqe.registration
GROUP BY mqe.registration
There could be a problem :) in duplicity rows... try to find one specific registration number, and compare the details of both query
SELECT *
FROM main_quick_enquiries
WHERE registration = XXXX
+
SELECT *
FROM main_quick_enquiries mqe
LEFT OUTER JOIN used_car_views ucv
ON ucv.numberplate = mqe.registration
WHERE registration = XXXX
you should see the diffs
谢谢大家,但我想我用COUNT(DISTINCT mqe.id)代替了COUNT(*)。
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