Hi, I am trying to put 'Product Category' to the POS Order Analysis. Still very new to OpenERP. So far I did:

In 'pos_order_report.py' add

'categ_id': fields.many2one('product.category','Category of Product', readonly=True),

to the pos_order_report class, and then

pt.categ_id as categ_id,
...
group by
...
pt.categ_id

in the SQL

In 'pos_order_report_view.xml' add

<field name="categ_id" invisible="1"/>

in the view_report_pos_order_tree and

 <field name="categ_id"/>

in view_report_pos_order_search

The Error it shows when I try to filter by "Category of Product" is:

ProgrammingError: Column report_pos_order.categ_id does not exist

LINE 1: ...HERE (("report_pos_order"."year" = '2013') AND ("report_po...

What am I doing wrong?