PL/SQL - changing one column's value depending another column's value

[uninvitedm]

I have a table which I'm extracting data from with a SELECT statement(and outputing as a text file), there's some changes I want to make to the extracted data before it is output (not the actual data on the table).

There's column1 and column2.
column1 has some null values. I want these values to be a certain value 'NB' if they are null AND if column2 is null as well! If there is a value in column2, then these can stay null. And if column1 already has a value (is not null) then I want to display that value..

How can I go about this in PL SQL? Thanks

[debasisdas]

try using the NVL function and do post back with your code that u have tried .

[uninvitedm]

try using the NVL function and do post back with your code that u have tried .

Thanks, sure. I've tried

nvl (column1||column2, 'NB') column1

Just returns '0' each time, and obviously displays both columns together.. was thinking along those lines

Also tried combining the two values using a DECODE so if both columns are null, show 'NB' for column1 -- but the following code

DECODE (column1||column2, 0, 'NB', column1) column1

doesn not work.. has the error 'invalid number'


EDIT: Scratch that, the decode with the 0 in quotes seems to work..... now i feel stupid.. thanks