[wp-trac] [WordPress Trac] #23369: WP_Comment_Query meta query 'count' conflicts with 'group by'

[WordPress Trac]

#23369: WP_Comment_Query meta query 'count' conflicts with 'group by'
-----------------------------+--------------------------
 Reporter:  heshiming        |       Type:  defect (bug)
   Status:  new              |   Priority:  normal
Milestone:  Awaiting Review  |  Component:  Comments
  Version:  trunk            |   Severity:  normal
 Keywords:                   |
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 This problem relates to {{{/wp-includes/comment.php}}}, both 3.5.1 and
 trunk are affected. The following line number refers to the 3.5.1 version.

 At line 195, definition of class {{{WP_Comment_Query}}} , a typical meta
 query will generate such SQL:

 {{{SELECT * FROM wp_comments INNER JOIN wp_commentmeta ON
 (wp_comments.comment_ID = wp_commentmeta.comment_id) WHERE (
 comment_approved = '0' OR comment_approved = '1' ) AND comment_post_ID =
 22 AND ( (wp_commentmeta.meta_key = 'my_flag' AND
 CAST(wp_commentmeta.meta_value AS CHAR) = 'my_value') ) GROUP BY
 wp_comments.comment_ID ORDER BY comment_date_gmt DESC }}}

 Note that at line 357, a meta query will always generate a {{{GROUP BY}}}
 clause. This works for comment rows. Say that I've got 3 comments matching
 this query, I'll see each of them in a row:

 {{{
 comment row 1, data
 comment row 2, data
 comment row 3, data
 }}}

 However, this query doesn't work well then {{{$count = true}}}. Note that
 by specifying {{{$count = true}}}, the function only changes {{{'SELECT
 *'}}} into {{{'SELECT COUNT(*)'}}}. For 3 comment result, I'm seeing
 something like this:

 {{{
 1
 1
 1
 }}}

 And you can see, because there's a {{{'GROUP BY'}}} clause. And each
 comment has a unique ID. The result is 3 'grouped row' of comments, and
 each will always have count of 1.

 Therefore, the result of {{{$wpdb->get_var()}}} will be either 1, or NULL
 (when nothing is matched). I believe this behavior is not by intention.

 To get count working, {{{'GROUP BY'}}} clause must be removed when $count
 is true.

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Ticket URL: <http://core.trac.wordpress.org/ticket/23369>
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