Zend\Db UNION DISTINCT
Need a UNION DISTINCT in Zend\Db?
It isn’t all that difficult, since it took me a while to figure out:
<?php
$select1 = new \Zend\Db\Sql\Select();
$select2 = new \Zend\Db\Sql\Select();
$select2->combine($select1,\Zend\Db\Sql\Select::COMBINE_UNION, 'distinct');
var_export($select2->getSqlString());
'( SELECT * ) UNION DISTINCT ( SELECT * )'