How to select the list of words containing a particular substring as part of a SQL query (oracle)? - sql

Question

I'm trying to return the list of "words" (separated by spaces) containing a certain substring within a string as part of an Oracle Sql query. Would like to return the result as a comma separated list. Separate rows for each match would also work.
Example String in [text_col] field:
some words 123-asdf-789A and also this one 456-asdf-555A more words etc.
Desired result: 123-asdf-789A, 456-asdf-555A
This is what I have so far but it only returns the first result and the fact that it's two separate regular expressions makes it difficult to concatenate all matches as I would like to do.
CONCAT(REGEXP_SUBSTR(text_col, ''(([^[:space:]]+)\asdf)'', 1, 1, ''i'', 1),
REGEXP_SUBSTR(text_col, ''\asdf([^[:space:]]+)'', 1, 1, ''i'', 1))

Answer 1

You can use some regexp functions together as :
with tab(str) as
(
select 'some words 123-asdf-789A and also this one 456-asdf-555A more words etc' from dual
), t as
(
select regexp_substr(str,'[^[:space:]]+',1,level) as str, level as lvl
from tab
connect by level <= regexp_count(str,'[:space:]')
)
select listagg(str,',') within group (order by lvl) as "Result"
from t
where regexp_like(str,'-');
Result
---------------------------------
123-asdf-789A,456-asdf-555A
Demo
first split by spaces (through [:space:] posix) and take the ones containing dash characters, and finally concatenate by listagg() function

Answer 2

Use a recursive sub-query factoring clause and iterate through all the matches concatenating the string as you go:
Oracle Setup:
CREATE TABLE test_data ( value ) AS
SELECT 'some words 123-asdf-789A and also this one 456-asdf-555A more words etc.' FROM DUAL UNION ALL
SELECT 'some words without the expected sub-string' FROM DUAL UNION ALL
SELECT 'asdf asdf-123 456-asdf 78-asdf-90' FROM DUAL
Query:
WITH matches ( value, idx, cnt, match ) AS (
SELECT value,
0,
REGEXP_COUNT( value, '\S*asdf\S*' ),
CAST( NULL AS VARCHAR2(4000) )
FROM test_data
UNION ALL
SELECT value,
idx + 1,
cnt,
CASE idx WHEN 0 THEN '' ELSE match || ' ' END
|| REGEXP_SUBSTR( value, '\S*asdf\S*', 1, idx + 1 )
FROM matches
WHERE idx < cnt
)
SELECT value, match
FROM matches
WHERE idx = cnt;
Output:
VALUE | MATCH
:----------------------------------------------------------------------- | :--------------------------------
some words without the expected sub-string | null
some words 123-asdf-789A and also this one 456-asdf-555A more words etc. | 123-asdf-789A 456-asdf-555A
asdf asdf-123 456-asdf 78-asdf-90 | asdf asdf-123 456-asdf 78-asdf-90
db<>fiddle here