$sql->select()
        ->columns(array('GroupedColum'
            ,'minValue' => new Expression('min(ValueColumn)')))
        ->from('ValueTable')
        ->group('GroupedColum')
        ->order('minValue')
        ->order('GroupedColum')
        ->limit(10);

$predicate = new ZendDbSqlPredicatePredicate();
$sql->where($predicate->greaterThan('filterColumn','20);

select GroupedColum
    , min(ValueColumn) as minValue
from ValueTable
where filterColumn > 20
group by GroupedColum
order by minValue
    GroupedColum
limit 10;

$predicate = new ZendDbSqlPredicatePredicate();

$predicate = new  ZendDbSqlWhere();

$sql->select()
    ->columns(array('GroupedColum'
        ,'minValue' => new Expression('min(ValueColumn)')))
    ->from('ValueTable')
    ->group('GroupedColum')
    ->order('minValue')
    ->order('GroupedColum')
    ->limit(10);
$predicate = new  ZendDbSqlWhere();
$sql->where($predicate->greaterThan('filterColumn','20);