One for the Tekkies: How to get this output using REGULAR EXPRESSIONS?

Question

How to get the below output using REGULAR EXPRESSIONS??
SQL> ed
Wrote file afiedt.buf
  1* CREATE TABLE cus___addresses    (full_address                   VARCHAR2(200 BYTE))
SQL> /
Table created.
SQL> PROMPT Address Format is: House #/Housename,  street,  City, Zip Code, COUNTRY
House #/Housename,  street,  City, Zip Code, COUNTRY
SQL> INSERT INTO cus___addresses VALUES('1, 3rd street, Lansing, MI 49001, USA');
1 row created.
SQL> INSERT INTO cus___addresses VALUES('3B, fifth street, Clinton, OK 74103, USA');
1 row created.
SQL> INSERT INTO cus___addresses VALUES('Rose Villa, Stanton Grove, Murray, TN 37183, USA');
1 row created.
SQL> SELECT * FROM cus___addresses;
FULL_ADDRESS
1, 3rd street, Lansing, MI 49001, USA
3B, fifth street, Clinton, OK 74103, USA
Rose Villa, Stanton Grove, Murray, TN 37183, USA
SQL> The REG EXP query shouLd output the ZIP codes: i.e. 49001, 74103, 37183 in 3 rows.Edited by: user12240205 on Jun 18, 2012 3:19 AM

Answer 1

Hi,
user12240205 wrote:
... Frank, ʃʃp's method, I understand. But your method, although correct, I find it difficult to understand.
Could you explain how you did this?? What does '.*(\d{5})\D*' and '\1' mean???
Your method is better because it uses only ONE reg expression function. ʃʃp's uses 2.In Oracle 10.2 (I believe) and higher, '\d' is equivalent to '[[:digit:]]', and '\D' is equivalent to '[^[:digit:]]'. I find '\d' and '\D' easier to type, but there's nothing wrong with using '[[:digit:]]' and '[^[:digit:]]'.
'.*' means "0 or more of any character".
'\D*' means "0 or more non-digits".
The whole expression, '.*(\d{5})\D*' means:
a. 0 or more characters (any characters)
b. 5 digits
c. 0 or more non-digits.
'\1' is a Backreference . It means the sub-string that matched the pattern after the 1st '(', up to (but not including) its matching ')'. In this case, that means the sub-string that matched '\d{5}', or b. using the explanation immediately above.
So the entire REGEXP_REPLACE call means "When you see a sub-string consisting of a., follwed immediately by b., followed immedately by c., replace that sub-string with b. alone."