Google Product feed error 1064

-- url of the page with the problem -- : www.pramhandwarmers.co.uk
-- HikaShop version -- : 2.3.4
-- Error-message(debug-mod must be tuned on) -- : 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') AND a.product_published=1 AND b.price_currency_id IN (1,2,4)' at line 1 SQL=SELECT a.*,b.* FROM c873h_hikashop_product AS a LEFT JOIN c873h_hikashop_price AS b ON a.product_id=b.price_product_id WHERE a.product_parent_id IN () AND a.product_published=1 AND b.price_currency_id IN (1,2,4)

Hello,

I just updated to new version and when I trigger Hikashop Google Products Plugin to get Google_data_feed.xml file it gives me following error and no data feed:

1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ') AND a.product_published=1 AND b.price_currency_id IN (1,2,4)' at line 1 SQL=SELECT a.*,b.* FROM c873h_hikashop_product AS a LEFT JOIN c873h_hikashop_price AS b ON a.product_id=b.price_product_id WHERE a.product_parent_id IN () AND a.product_published=1 AND b.price_currency_id IN (1,2,4)

I triggered the feed before the update and it was fine.

Any solutions?

Regards
Karel