DB Query in Drupal 7 - mysql

Question

I am trying to run a db query in drupal where, the content type has a node association field, and I am trying to get all notes of that type, where the NID of the current node matches any of the nodes specified in said note association field.
a visual example
Nodetype1
-- Node Association Field
NodeType2
I would like to get all Nodetype1's where Node Association Field matches the NID of Nodetype2 that is currently loaded.
My current db query is like so:
db_query("SELECT * FROM field_data_field_promo_profile WHERE field_promo_profile_nid=".$N->nid);
and this returns nothing, when i know for a fact that such a node exists, I also tried dropping the WHERE statement and it returns an array like this:
DatabaseStatementBase Object ( [dbh] => DatabaseConnection_mysql Object ( [shutdownRegistered:protected] => [target:protected] => default [key:protected] => default [logger:protected] => [transactionLayers:protected] => Array ( ) [driverClasses:protected] => Array ( [SelectQuery] => SelectQuery [DatabaseSchema] => DatabaseSchema_mysql [MergeQuery] => MergeQuery [DatabaseTransaction] => DatabaseTransaction [UpdateQuery] => UpdateQuery [InsertQuery] => InsertQuery_mysql ) [statementClass:protected] => DatabaseStatementBase [transactionSupport:protected] => 1 [transactionalDDLSupport:protected] => [temporaryNameIndex:protected] => 0 [connectionOptions:protected] => Array ( [database] => cityhound_dev [username] => blahblah [password] => blahblah [host] => localhost [port] => [driver] => mysql [prefix] => Array ( [default] => ) ) [schema:protected] => DatabaseSchema_mysql Object ( [connection:protected] => DatabaseConnection_mysql Object *RECURSION* [placeholder:protected] => 0 [defaultSchema:protected] => public [uniqueIdentifier:protected] => 4fd7fba9e563e2.50177866 ) [prefixes:protected] => Array ( [default] => ) [prefixSearch:protected] => Array ( [0] => { [1] => } ) [prefixReplace:protected] => Array ( [0] => [1] => ) ) [queryString] => SELECT * FROM field_data_field_promo_profile )
Any one have some ideas ?

Answer 1

db_query() returns an iterable object, so you just need to iterate over it:
$result = db_query("SELECT * FROM field_data_field_promo_profile WHERE field_promo_profile_nid=".$N->nid);
foreach ($result as $row) {
$entity_id = $row->entity_id;
// etc...
}

Answer 2

You should use parameters in your queries to prevent SQL injections.
For instance the query above should look like this:
$result = db_query("SELECT * FROM {field_data_field_promo_profile} p
WHERE p.field_promo_profile_nid = :nid ", array(':nid' => $N->nid);
foreach ( $result as $row ) {
$entity_id = $row->entity_id;
// etc...
}