Count distinct not allowed in Analytical function in Impala

[#1]

SELECT COUNT(DISTINCT cust_n) OVER(PARTITION BY ord_id,ord_d) cusp_cnt FROM table1;

-- Not working in Impala. Is there any way to overcome the issue.

[#2]

Hi Nick,

Can you please share what do you mean by not working? Error messages would be helpful here.

Cheers