Question

I would like some help with the following regexes.

00  should be replaced by Null
01  should be left as it is
0   should be replaced by Null

if there is a single 0 or two 0’s then they should be replaced by Null’s

My try is

select regexp_replace('0','^0',NULL) from dual

but my code will not work correct for 01

Got this to work using

select regexp_replace('01','^0(0)?',NULL) from dual

Answer 1

Does this work?

select regexp_replace('0','^0+$',NULL) from dual

I believe this should replace a string which just contains 0’s with NULL.

I got the oracle regex syntax from here.

If you do only wish to update strings of one or two zeros, use the following:

select regexp_replace('0','^0{1,2}$',NULL) from dual

or

select regexp_replace('0','^0(0)?$',NULL) from dual