Question

The following query returns strange results for me:

SELECT     `Statistics`.`StatisticID`,     COUNT(`Votes`.`StatisticID`) AS `Score`,     COUNT(`Views`.`StatisticID`) AS `Views`,     COUNT(`Comments`.`StatisticID`) AS `Comments` FROM `Statistics` LEFT JOIN `Votes` ON `Votes`.`StatisticID` = `Statistics`.`StatisticID` LEFT JOIN `Views` ON `Views`.`StatisticID` = `Statistics`.`StatisticID` LEFT JOIN `Comments` ON `Comments`.`StatisticID` = `Statistics`.`StatisticID` GROUP BY `Statistics`.`StatisticID` LIMIT 0, 10 

I’m querying this on a table structure like the following:

(only data relevant to Statistics.StatisticID = 8)

Votes

StatisticID     8 

Views

StatisticID     8     8 

Comments

StatisticID     8     8     8     8     8 

Now if I run this query I get the following result set:

StatisticID    Score    Views   Comments      8           5        5        5 

I knwo where the 5 comes from – the number of Comments – and this works if I take the comments statement out. Can anyone debug this as this is out of my reach (I’m relatively new with SQL).

Thanks, Ross

Answer 1

Assuming you have an id field or similar on the votes/views/comments:

SELECT     `Statistics`.`StatisticID`,     COUNT(DISTINCT `Votes`.`VoteID`) AS `Score`,     COUNT(DISTINCT `Views`.`ViewID`) AS `Views`,     COUNT(DISTINCT `Comments`.`CommentID`) AS `Comments` FROM `Statistics` LEFT JOIN `Votes` ON `Votes`.`StatisticID` = `Statistics`.`StatisticID` LEFT JOIN `Views` ON `Views`.`StatisticID` = `Statistics`.`StatisticID` LEFT JOIN `Comments` ON `Comments`.`StatisticID` = `Statistics`.`StatisticID` GROUP BY `Statistics`.`StatisticID` LIMIT 0, 10 

Not tested it, but think it should work. (We have to use the different field because the statisticID will always be the same within a given group …)