ORA-24347: Warning of a NULL column in an aggregate function with PHP5.3.3

问题

Problem Statement: I am getting the below error with php5.3.3. ORA-24347: Warning of a NULL column in an aggregate function. Same coding was working fine with php4. There is no issue with my oracle view but when I started using the same with php5.3.3. It started giving the warning.

Query:

  CREATE OR REPLACE FORCE VIEW "CUSTOMER_OA" ("CUST_ID", "CUSTOMER", "OPEN_CT", "EXPIRE_SOON_CT", "INVALID_EMAIL_CT") AS 
    select c.cust_id, initcap(max(c.name)) AS customer,  null AS open_ct, null AS expire_soon_ct, count(unique invalid.contact_id) AS invalid_email_ct
    from customer c
    inner join apptype at
    using (apptype_id)
    left outer join (select cust_id, contact_id from cust1 where valid_email = 'N'
    union all
    select cust_id, contact_id from cust2 where valid_email = 'N'
    union all
    select cust_id, contact_id from cust3 where valid_email = 'N') invalid
    on (c.cust_id = invalid.cust_id)
    where at.app_type = '1' 
    group by c.cust_id
    order by customer;

来源：https://stackoverflow.com/questions/40926515/ora-24347-warning-of-a-null-column-in-an-aggregate-function-with-php5-3-3