Hi All,
I have a table sales. I need to fetch active customers based on expiry date .
My query is
select active_cust from sales where exp_date is null .
Here active customers are taken based on expiry date is null. If we use is null condition in where clause will it affect its search as my understanding is null is an unknown value and oracle needs to scan entire table. Is there any way to avoid this 'is null' condition ? shall I use functional index on 'is null ' condition .please kind your advice.
Regards,
Uday