oracle 9.2 sql plus IF NULL

I am trying to write a select statement that will ask the user for a variable

table

Name number dept

John    1         acc
Iain    2         acc
Martin  3         sales
Bobby   4         IT

Select * from table

where dept = '&Input'

The user can key in the dept but if it is blank all records are display. How do I code this

Thanks in advance
Colin Received on Fri Feb 20 2004 - 02:49:38 CST