How to use GROUP_CONCAT with Zend Framework?

Question

Assume that I have a table : students

______________________________________________________
|id   | name           | school        | class        |
______________________________________________________
| 1   | John           | ABC           | C1           |
| 2   | Jack           | ABC           | C1           |
| 3   | Anna           | ABC           | C1           |
| 4   | Peter          | DEF           | D1           |
| 5   | Alex           | ABC           | C2           |
| 6   | Bryan          | ABC           | C2           |
| 7   | David          | ABC           | C2           |
| 8   | Cristian       | DEF           | D1           |
_______________________________________________________

Using this query :

 SELECT a.class,GROUP_CONCAT(a.name) as names FROM students a WHERE a.school='ABC' GROUP BY a.class 

give me this result :

 ____________________________
|class  | names             |
 ____________________________
| C1    | John, Jack, Anna  |
| C2    | Alex, Bryan, David|
 ____________________________

How can I execute this query in Zend Framework by using Zend_Db_Table or Zend_Db_Select? Thank you so much!

Answer 1

Zend Expression gave me problems, the easiest way for me was:

$select->from($this,
    array(
         'listings.*',
         '(SELECT GROUP_CONCAT(DISTINCT ecg.listing_cat_name,"*|*",ecg.listing_cat_id SEPARATOR "-|-") FROM listings_cats AS ecg 
LEFT JOIN listings_to_listings_cats ON listings_to_listings_cats.listing_cat_id=ecg.listing_cat_id
WHERE listings_to_listings_cats.listing_id=listings.listing_id
LIMIT 7 ) AS catGrouping'))

Here I'm concatenating a list of category names and ids, which I explode in my search results and print a list of clickable child categories per parent record. You can obviously add further Joins and other conditions to the from() as the above will be treated as a sub query.

Answer 2

I guess it will be something like this. Try it.

$table = Your_DbTable_Class();
$select = $table->select()
          ->setIntegrityCheck(false)
          ->from(array('a' => 'students'), array( 'class' => 'class' , 'names' => new Zend_Db_Expr('GROUP_CONCAT(a.name)')) )
          ->where( 'a.school = ?', 'ABC' ) 
          ->group('a.class');

When I assemble it, it gives me following query:

SELECT `a`.`class`, GROUP_CONCAT(a.name) AS `names` FROM `students` AS `a` 
WHERE (a.school = 'ABC')
GROUP BY `a`.`class`

Is it what you are looking for ?