Multi statement queries in Civireport
@Dino62 - I dont think you can execute multiple SQL at the same time 

But still you can split the SQL in to different task and create a temp table and input all the values which you want to display in the report 

Use the below to run the SQL against Database separately 

CRM_Core_DAO::executeQuery( $query, $sqlParams );


If the above is not helping then try to use 

function alterRow( &amp;$row ) {
    $row['sort_name'] .= ' ( altered )';
}


where you can handle each row individually 

I guess this helps !!!