Oracle 10g: Connect by prior

Question

What is the difference between using PRIOR in

CONNECT BY  CUST_ID=  PRIOR  CUST_CUST_ID

and

CONNECT BY  PRIOR CUST_ID=   CUST_CUST_ID

?

Answer 1

Prior defines parent row.

In your case: CONNECT BY PRIOR CUST_ID = CUST_CUST_ID search for the next row (parent) where cust_id is equals to cust_cust_id from the current row.

CONNECT BY CUST_ID = PRIOR CUST_CUST_ID search for the next row (parent) where cust_cust_id is equals to cust_id from the current row.