getting customer group using Grid control

Question

I would like to get the customer group in Sales > Order grid. I'm using the gridcontrol module for this.

I used below XML tag to get customer group but after that I do not see any order. I think my join query is wrong:

<join table="customer/customer_group" condition="main_table.customer_id ={{table}}.customer_group_id" field="customer_group_code"/>

Answer 1

It is, as you're joining a customer id with a customer group id. The main_table is sales_flat_order. It has a customer_group_id field, which can be NULL.