Testing for <NULL> Parameters in SQL*PLUS

One can run a SQLPLUS script as follows:-

        SQLPLUS SCOTT/TIGER _at_SCRIPT.SQL PARAM1

where the value in 'PARAM1' is used for &1. But if the user has not typed in 'PARAM1' how can you test for this in the 'script' without SQL*PLUS 'asking' for &1?

What I want to do is to be able to run a script with a param (eg. to sort by a particular column) or if I don't give a parameter to use a particular column to sort on by default.

I Tried using a construct like (nvl('&1','default')) but SQL*PLUS stills wants a null reply to &1 before it will use 'default' eg. in a decode statement.

(I would prefer a SQL*PLUS script which can be STARTable from within SQL*PLUS rather than a 'here is' unix script)

Lez

-- 
Lez Oxley, Administration, University of Sussex, Brighton, BN1 9RH, UK
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