Re: LEFT JOIN not working
| From: | Ignatius Reilly | Date: | Thu, 09 Jan 2003 10:07:17 +0000 |
| Subject: | Re: LEFT JOIN not working | ||
| References: | 1 | Groups: | php.db |
| Request: | Send a blank email to php-db+get-24692@lists.php.net to get a copy of this message | ||
problem 1:
move the WHERE clauses to the ON clauses
problem 2:
Obviously your intent with " COUNT(ads_clickrate.date) " is to count the
number of non-null occurences of click. But COUNT() is not the appropriate
function to do this (it will simply give you the number of rows inside a
group).
Try replacing COUNT(ads_clickrate.date) by SUM( IF( ads_clickrate.date IS
NULL, 0, 1 ) )
HTH
Ignatius
____________________________________________
----- Original Message -----
From: "Lisi" <lists@shemeshdirectory.co.il>
To: "PHP-DB" <php-db@lists.php.net>
Sent: Thursday, January 09, 2003 10:44 AM
Subject: [PHP-DB] LEFT JOIN not working
> I have a page with many ads that stores both the number of times an ad is
> displayed and how many times it gets clicked. These are stored in two
> different tables (since different information is stored for each) but both
> have identical name columns. I am trying to display both # times displayed
> and # times clicked in the same table in an admin page.
>
> Here is my query:
>
> SELECT ads_clickrate.name, ads_clickrate.link, SUM(ads_displayrate.count)
> as display, COUNT(ads_clickrate.date) as click FROM ads_displayrate LEFT
> JOIN ads_clickrate ON ads_displayrate.name = ads_clickrate.name WHERE
> YEAR(ads_clickrate.date) = '2003' AND MONTH(ads_clickrate.date) = '01'
> GROUP BY ads_clickrate.name ORDER BY ads_clickrate.name
>
> I want to display for each ad the number of times displayed, and then
> number of times clicked if applicable, if not 0.
>
> The query is only returning rows for ads that have been clicked on. Is the
> problem because I have a COUNT column for one table, with a group by? Is
> this causing the display to be grouped also?
>
> If you need more information how the table is set up let me know, I'm
> really stumped here.
>
> Thanks,
>
> -Lisi
>
>
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