Parsing one col of multiple rows php

Question

I have e.g. the following data returned from a query, each name is an item:

id      name      comment
1       FF        hey
1       FF        hey back!
2       L         


        

Answer 1

You can use GROUP_CONCAT() on your mysql query to group all the comments together for each name

SELECT id, name
GROUP_CONCAT(comment) AS comment
FROM table
GROUP BY name;

then explode() the $row[comment] in your php code

while ($row = mysql_fetch_array($result)){

echo '
'.$row['name'].'
';

    if($row['comment'] != ""){

       $comments = explode(",",$row['comment']);
       foreach($comments as $comment){
               echo '
'.$comment.'
';
       } 

    }

echo '
';

}

Edit
Thanks to @CBroe, I now know that GROUP_CONCAT() has a group_concat_max_len default of 1024. You will want to increase this before running the GROUP_CONCAT() query -

SET [GLOBAL | SESSION] group_concat_max_len = 10240; // must be in multiples of 1024
SELECT id, name
GROUP_CONCAT(comment) AS comment
FROM table
GROUP BY name;

you will also need to be aware of max_allowed_packet as this is the limit you can set var_group_concat_max_len to.

note: mysql_query() does not allow multiple queries, so you will need to do 2 mysql_query(), and you can use SET SESSION ... so that all queries in your current session have that max_len. It would be better to change from mysql_ functions (which are depreciated) and change to mysqli_ or PDO as they offer multiple query option. also check out - http://php.net/manual/en/mysqlinfo.api.choosing.php