how to direct select output to insert input

[Net Llama!]

i've got an Oracle (9i, if that matters) problem.  i need to essentially 
copy all the data from a single column (call it a) in a table into a 
different column (call it b) in the same table.  both a and b are the 
same datatype, and b is currently empty.  i've tried the following, but 
it fails:
insert into table_foo (b) values ((select a from table_foo));

i think the problem is that its attempting to insert all the rows from a 
into a single row of b.  i just don't know how to work around this. 
anyone have any ideas or suggestions?  thanks!

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
L. Friedman                       	       netllama at linux-sxs.org
Linux Step-by-step & TyGeMo: 		    http://netllama.ipfox.com

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