Multiple where conditions giving SQL error

[DavidOliver]

Version: 0.6.2 (Symphony 2.2.5)

I have the following in an event:

$products_query = new SymQLQuery();
$products_query
    ->select('name, brand, instances')
    ->from('products')
    ->perPage(999);
foreach ($_SESSION['sym-cart'] as $key => $item) {
    $products_query->where('instances', $key);
}
$products = SymQL::run($products_query);

The instances field is a SBL+ field.

When there is more than one product in the cart, meaning ->where is called more than once, and the event is triggered:

Symphony Fatal Database Error Not unique table/alias: 't137' An error occurred while attempting to execute the following query SELECT SQL_CACHE e.id, e.section_id, e.author_id, UNIX_TIMESTAMP(e.creation_date) AS creation_date FROM sym_entries AS e LEFT JOIN sym_entries_data_137 AS t137 ON (e.id = t137.entry_id) LEFT JOIN sym_entries_data_137 AS t137 ON (e.id = t137.entry_id) WHERE 1 AND e.section_id = '1' AND t137.relation_id IN ('1723') AND t137.relation_id IN ('3096') ORDER BY e.idDESC LIMIT 0, 999

The t137 alias is created more than once.

When ->where is called multiple times using system:id, this error doesn't occur.