Database: tables Join

[Bazilisk]

Have error in this script in Application system. I have 2 records in array if have record in table news_upload.

$select = \IPS\Db::i()->select( '*', 'news_news', NULL, 'news_artcms_news.num DESC', array( 0, 25 ) );
$select = $select->join( 'news_uploads', 'news_uploads.recordNum=news_news.num', 'LEFT' );
$results = \IPS\Db::i()->query($select);

Where is my mistake?

Next code work Ok in block system. 

$select = $connection->select( '*', 'news_news', NULL, 'news_news.num DESC', array( 0, 25 ) );
$select = $select->forceIndex( 'num' ); 
$select = $select->setKeyField( 'num' );
$select = $select->join( 'news_uploads', 'news_uploads.recordNum=news_news.num', 'LEFT' );
$results = \count($select); 

But in application system I have error for forceIndex() and setKeyField.

Think what problem because tables have field 'num', and select get this from second table, but I have to get it from first....

Possible using distinct can decide this task, but can not find sintax.

Edited April 24, 2021 by Bazilisk

[Daniel F]

What's the returned error?