How do I extract a pattern from a table in Oracle 11g?

I want to extract text from a column using regular expressions in Oracle 11g. I have 2 queries that do the job but I'm looking for a (cleaner/nicer) way to do it. Maybe combining the queries into one or a new equivalent query. Here they are:

Query 1: identify rows that match a pattern:

select column1 from table1 where regexp_like(column1, pattern);

Query 2: extract all matched text from a matching row.

select regexp_substr(matching_row, pattern, 1, level) 
from dual
connect by开发者_开发百科 level < regexp_count(matching_row, pattern);

I use PL/SQL to glue these 2 queries together, but it's messy and clumsy. How can I combine them into 1 query. Thank you.

UPDATE: sample data for pattern 'BC':

row 1: ABCD
row 2: BCFBC
row 3: HIJ
row 4: GBC

Expected result is a table of 4 rows of 'BC'.

---

You can also do it in one query, functions/procedures/packages not required:

WITH t1 AS (
SELECT 'ABCD' c1 FROM dual
UNION
SELECT 'BCFBC' FROM dual
UNION
SELECT 'HIJ' FROM dual
UNION
SELECT 'GBC' FROM dual
)
SELECT c1, regexp_substr(c1, 'BC', 1, d.l, 'i') thePattern, d.l occurrence
  FROM t1 CROSS JOIN (SELECT LEVEL l FROM dual CONNECT BY LEVEL < 200) d
WHERE regexp_like(c1,'BC','i')
   AND d.l <= regexp_count(c1,'BC');

C1    THEPATTERN           OCCURRENCE
----- -------------------- ----------
ABCD  BC                            1
BCFBC BC                            1
BCFBC BC                            2
GBC   BC                            1

SQL>

I've arbitrarily limited the number of occurrences to search for at 200, YMMV.

---

Actually there is an elegant way to do this in one query, if you do not mind to run some extra miles. Please note that this is just a sketch, I have not run it, you'll probably have to correct a few typos in it.

create or replace package yo_package is
  type word_t  is record (word varchar2(4000));
  type words_t is table of word_t;
end;
/

create or replace package body yo_package is

  function table_function(in_cur in sys_refcursor, pattern in varchar2) 
  return words_t
    pipelined parallel_enable (partition in_cur by any)
  is
    next varchar2(4000);
    match varchar2(4000);
    word_rec word_t;
  begin
    word_rec.word = null;

    loop

    fetch in_cur into next;
    exit when in_cur%notfound;

    --this you inner loop where you loop through the matches within next
    --you have to implement this 
    loop
        --TODO get the next match from next     
        word_rec.word := match;
        pipe row (word_rec);    
    end loop;

    end loop;

  end table_function;

end;
/


select  *
from table(
    yo_package.table_function(
        cursor(
            --this is your first select
            select column1 from table1 where regexp_like(column1, pattern)
        )
    )