PHP PDO SQL Server Null result causes exception - php

Question

I have a PDO class so I can easily switch between database types.
//*** Function: createQuery, Purpose: Create the query object ***
function createQuery($theQuery)
{
$theQuery = str_replace('`', "'", $theQuery);
$this->query = $theQuery;
$this->sth = $this->pdo->prepare($theQuery, array(PDO::ATTR_CURSOR
=> PDO::CURSOR_FWDONLY));
}
//*** Function: query, Purpose: Execute the PDO ***
function query($paramArray = [], $column = null)
{
try
{
if(!empty($paramArray))
foreach ($paramArray as $key => &$val)
{ $this->sth->bindParam($key, $val);}
$this->sth->execute();
}
catch(PDOException $e) { $this->error_catcher( $e->getMessage());}
if($column != null)
{
$column = ($this->sth->columnCount() < $column) ? 0 : $column;
return $this->sth->fetchAll( PDO::FETCH_COLUMN, $column );
}
else
return $this->sth->fetchAll();
}
and it all works spiffingly well. However, sometimes, if the result is NULL the code throws an exception
here is a typical query to build a menu :
SELECT TOP (100) PERCENT caption, id
FROM dbo.com_menuitems
WHERE (suite = 'chrimbotu') AND (parentid = 0) AND (enabled = 1) AND (id IN
(
SELECT parentid AS id FROM dbo.com_menuitems AS com_menuitems_1
WHERE (suite = 'chrimbotu') AND (perms <= - 1)GROUP BY parentid
HAVING (parentid > 0))
)
ORDER BY parentid, vieworder, caption
and i load the query (from another script) like this :
function getTopLevel($mySQL)
{
$this->_myConn->createQuery($mySQL);
$result = $this->_myConn->query() or die (DumpSQL($mySQL).__FUNCTION__ .' Query failed.');
$this->_topLevel = $result[0]['perms'];
}
If I run the query with no 'chrimbotu' in the database, SSMS says [NULL, NULL] my script carks and throws the helpful error "Query failed".
If I add 'chrimbotu' to the database, but give it a perms of 9, SSMS says [NULL, NULL] but my script is happy.
Both queries return a NULL, but is one more "NULLER" than the other?
FYI: 0 is the lowest permission, < 0 is "everybody" stuff