How to JOIN tables with $wpdb

  • I want to JOIN $wpdb->comments with commentmeta. Im only trying to get the field “meta_value”.

    global $wpdb;
$commentQ = "SELECT * FROM $wpdb->comments " . $whereClause . $orderBy;
$comments = $wpdb->get_results( $commentQ, ARRAY_A);

// build the string

$commentString = "";
$count = 0;
if( $comments ){
    $first = true;
    foreach( $comments as $row ){
        if( $first ){
            // column labels
            foreach ( $row as $col => $value ){
                    //$commentString .= $col . chr( 9 );

    After i join the tables i want to get “meta_value” from wp_commentmeta_88 and insert it instead of “comment_author”

    // Column Author
                if($col == 'comment_author') {
                $commentString .= 'User Meta        ';
                }           

            // Column IP
            if($col == 'comment_author_IP') {
                $commentString .= '   IP    ';
            }       

            // Column date
            if($col == 'comment_date') {
                $commentString .= '                Datum    ';
            }   

            // Column comment
            if($col == 'comment_content') {
                $commentString .= '                Meddelande   ';
            }                                           

            }
            $commentString .= chr( 13 );
            $first = false;
        }

    [please remember to mark any posted code – https://codex.www.ads-software.com/Forum_Welcome#Posting_Code ]

Viewing 6 replies - 1 through 6 (of 6 total)
  • Moderator bcworkz

    (@bcworkz)

    Why not use get_comment_meta()? I would directly answer you question, but I don’t know how to do table joins either ??

    This is a pretty generic MySQL join that will work with what you want. You might have to change the fields that you are looking for, condtions, etc.

    SELECT m.meta_value AS meta_value
FROM wp_commentmeta AS m
INNER JOIN wp_comments AS c
ON c.comment_id = m.comment_id
AND c.comment_id = 1234
    Thread Starter Meiioo

    (@meiioo)

    bcworkz:
    Im not using get_comment_meta() because this is a plugin to export comments I’m editing. And i was told to not use get_meta.

    michael.mariart:

    Could you explain little more ?
    Is your solution the same solution as what I’m trying to do ?
    Or is it a different way but do the same ?

    From what you said at the start, yes this is exactly what you are trying to do. It will grab the meta_value from the DB that relates to the comment. You just have to change the ID’s that you use to get the value that you want.

    Thread Starter Meiioo

    (@meiioo)

    Look at my second block of code where i output the fields to export etc comment_author.

    Im going to remove that comment_author and i want the value of meta_value for the other table.

    S? basicly i understan your INNER JOIN but i dont understand wich id i should put down there.

    If you understand the join then the ID should be easy to see. The one that you need to look at is ‘c.comment_id’. That’s the ID of the comment that you want to get the vlaue for so that’s the one that you need to change.

Viewing 6 replies - 1 through 6 (of 6 total)
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