[SQL] Inconsistent usage of Index

Hi All, I have attached file explaining inconsistent usage of Index. Thanks, Subra __ Do You Yahoo!? Get personalized email addresses from Yahoo! Mail - only $35 a year! http://personal.mail.yahoo.com/

[SQL] Index usage

Hi All, The index created by me is not being used while doing select. I found that out by using the EXPLAIN. For example: Table department has dept_num dept_desc Table 'employee' looks like this: emp_num primary key, emp_name, dept_num (this i