Zend Framework 2: sql subquery

Question

In ZF1 it worked like this:

 $selectColumns = array(
   '*',
   'orders_total' => "(".$db->select()->from("orders", array("COUNT(*)"))->where("orders.parent_id=mytable.id").")",
 );
 $select = $db->select()->from('mytable', $selectColumns);

How to do this in the ZF2? Thanks.

Answer 1

Please try this.

$sql = new Sql($this->_adapter);
$mainSelect = $sql->select()->from('mytable');
$subQry = $sql->select()
        ->from('orders')
        ->columns(array('orderCount' => new \Zend\Db\Sql\Expression('COUNT(orders.id)')));
$mainSelect->columns(
        array(
            'id', 
            'orders_total' => new \Zend\Db\Sql\Expression('?', array($subQry)),
        )
);

$statement = $sql->prepareStatementForSqlObject($mainSelect);
$comments = $statement->execute();
$resultSet = new ResultSet();
$resultSet->initialize($comments);

return $resultSet->toArray();

Link: ZF2 - subqueries

Answer 2

You can try this:

// Make your query here using the builder if you wish, 
// but we will need to convert to string for the Expression
$sub = new Select('orders');
$sub->columns(array(new Expression('COUNT(*) as total')))
    ->where(array('id' => 4))
;
// You could just create an expression..
$subquery = new \Zend\Db\Sql\Expression("({$sub->getSqlString()})");

$select = new \Zend\Db\Sql\select('tablename'); // this is inside a 

$select->columns(array('*', 'orders_total' => $subquery));

the output will be something like this:

SELECT 
    .*, 
    (SELECT COUNT(*) as total FROM "orders" WHERE "id" = '4') AS orders_total 
FROM tablename

I haven't figured out a nice way of using the query builder to perform these kind of queries without having to use raw queries.