Filtering data from an array which is a result from mysql query

Question

Okay I have a query that looks like this :

   "SELECT `tag_name`,`sub_tag_name` FROM phpro_tag_targets targets
    INNER JOIN  sub_tags ON targets.sub_tag_id=sub_tags.sub_tag_id
    INNER JOIN phpro_tags tags ON targets.tag_id=tags.tag_id
    WHERE tag_target_id='{$vid['tag_target_id']}'";

The tables themselves looks like this:

phpro_tag_targets:

   tag_target_id | tag_id  | sub_tag_id | tag_target_name | tag_type_id
     int(11)     | int(11) | int(11)    |  var_char        | int(3)
    <PK - index> |   <fk>  |  <fk>    

phpro_tags:

  tag_id | tag_name
   <PK>  | VARCHAR
  sub_tags:
   sub_tag_id | sub_tag_name
     <PK>     | VARCHAR

and the result of the query looks something like this

Array ( 
    [0] => Array ( [tag_name] => Humanity [sub_tag_name] => Children ) 
    [1] => Array ( [tag_name] => Society [sub_tag_name] => Children ) 
    [2] => Array ( [tag_name] => Art and Artists [sub_tag_name] => Creativity ) 
    [3] => Array ( [tag_name] => Humanity [sub_tag_name] => Creativity ) 
    [4] => Array ( [tag_name] => Humanity [sub_tag_name] => Culture ) 
    [5] => Array ( [tag_name] => Society [sub_tag_name] => Culture ) 
    [6] => Array ( [tag_name] => unlisted [sub_tag_name] => Culture ) 
    [7] => Array ( [tag_name] => unlisted [sub_tag_name] => Culture ) 
)

The result is the tags and subtags associated with a piece of content (ie. video or article). I am attempting to display this information in html such that I have a <span class="tags"> and a <span class="subtags">. For the above eg. data the html would look like this:

   <span class="tags"> Humanity Society Art and Artists unlisted </span>
   <span class=subtags> Children Creativity Culture </span>

Is there a way that I can somehow filter data using php (or altering the query) so that I am only displaying Each different value a single time. As I am currently using a loop to cycle through the dat and displaying the same tag, and subtags multiple times, but can't figure out how to further filter the result.

An insight into how I could do this would be greatly appreciated!

Answer 1

First you need to loop through the data array and collect all tag names and subtag names into separate arrays. Then use array_unique to remove duplicate values from an array. And finally use implode to join array elements to a string.

$tags = array();
$sub_tags = array();

// NOTE: $array is query result array
foreach ( $array as $value ) {
    $tags[] = $value['tag_name'];
    $sub_tags[] = $value['sub_tag_name'];
}

$tags = array_unique( $tags );
$sub_tags = array_unique( $sub_tags );

echo '<span class="tags">'.implode( ' ', $tags ).'</span>';
echo '<span class="subtags">'.implode( ' ', $sub_tags ).'</span>';

I really hope that I have correctly understood the question.

Answer 2

Here is how you can edit your query to give you a one line result with what I think you need. The GROUP_CONCAT function with the DISTINCT option and a SEPARATOR of ' ' should give you the format you are going for.

SELECT GROUP_CONCAT(DISTINCT `tag_name` SEPARATOR ' '),
       GROUP_CONCAT(DISTINCT `sub_tag_name`SEPARATOR ' ') 
FROM phpro_tag_targets targets
INNER JOIN sub_tags ON targets.sub_tag_id=sub_tags.sub_tag_id
INNER JOIN phpro_tags tags ON targets.tag_id=tags.tag_id
WHERE tag_target_id='{$vid['tag_target_id']}'

The output for this will be

tag_name | sub_tag_name
Humanity Society Art and Artists unlisted | Children Creativity Culture