question about regexp_substr

I have some difficulty understanding applying an operator to the pattren in regexp_substr. Not sure if anyone can help ?

The question is, what is the difference between these two queries:

select regexp_substr('A1B2C3D4E', '[^0-9]+', 1, 3) from dual;

R
-

C

select regexp_substr('A1B2C3D4E', '[^0-9]*', 1, 3) from dual;

R
-

B

Why * and + gives different answers?

Thanks in advance

Alex

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http://www.freelists.org/webpage/oracle-l Received on Tue Dec 16 2014 - 22:06:50 CET