Zend Framework 2: sql subquery - php

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.

Answer 3

Without any more info you could try:
$selectColumns = array(
'*',
'orders_total' => "(".$db->select()->from("orders", array("COUNT(*)"))->where("orders.parent_id", "mytable.id").")",
);
$select = $db->select()->from('mytable', $selectColumns);
You will need to add at top with the use statements:
use Zend\Db\Sql\Select;
use Zend\Db\Sql\Where;

Answer 4

You can try restructuring your SQL to something like:
SELECT
*,
SUM(IF(O.parent_id IS NULL, 0, 1)) AS orders_total
FROM mytable
LEFT JOIN orders O ON mytable.id = O.parent_id
Which you can represent using Zend Framework 2 as:
$select = new Select('mytable');
$select->columns(array(
'*',
'orders_total' => new Expression("SUM(IF(O.parent_id IS NULL, 0, 1))")
));
$select->join(array('O', 'orders'),
"mytable.id = O.parent_id",
Select::JOIN_LEFT);
$select->group(array('mytable.id'));
$result = $dbh->selectWith($select);
Assuming $dbh is your database adapter.