Split string by space and character as delimiter in Oracle with regexp_substr - sql

Question

I'm trying to split a string with regexp_subtr, but i can't make it work.
So, first, i have this query
select regexp_substr('Helloworld - test!' ,'[[:space:]]-[[:space:]]') from dual
which very nicely extracts my delimiter - blank-blank
But then, when i try to split the string with this option, it just doesn't work.
select regexp_substr('Helloworld - test!' ,'[^[[:space:]]-[[:space:]]]+')from dual
The query returns nothing.
Help will be much appreciated!
Thanks

Answer 1

SQL Fiddle
Oracle 11g R2 Schema Setup:
CREATE TABLE TEST( str ) AS
SELECT 'Hello world - test-test! - test' FROM DUAL
UNION ALL SELECT 'Hello world2 - test2 - test-test2' FROM DUAL;
Query 1:
SELECT Str,
COLUMN_VALUE AS Occurrence,
REGEXP_SUBSTR( str ,'(.*?)([[:space:]]-[[:space:]]|$)', 1, COLUMN_VALUE, NULL, 1 ) AS split_value
FROM TEST,
TABLE(
CAST(
MULTISET(
SELECT LEVEL
FROM DUAL
CONNECT BY LEVEL < REGEXP_COUNT( str ,'(.*?)([[:space:]]-[[:space:]]|$)' )
)
AS SYS.ODCINUMBERLIST
)
)
Results:
| STR | OCCURRENCE | SPLIT_VALUE |
|-----------------------------------|------------|--------------|
| Hello world - test-test! - test | 1 | Hello world |
| Hello world - test-test! - test | 2 | test-test! |
| Hello world - test-test! - test | 3 | test |
| Hello world2 - test2 - test-test2 | 1 | Hello world2 |
| Hello world2 - test2 - test-test2 | 2 | test2 |
| Hello world2 - test2 - test-test2 | 3 | test-test2 |

Answer 2

If i understood correctly, this will help you. Currently you are getting output as Helloworld(with space at the end). So i assume u don't want to have space at the end. If so you can simply use the space in the delimiter also like.
select regexp_substr('Helloworld - test!' ,'[^ - ]+',1,1)from dual;
OUTPUT
Helloworld(No space at the end)
As u mentioned in ur comment if u want two columns output with Helloworld and test!. you can do the following.
select regexp_substr('Helloworld - test!' ,'[^ - ]+',1,1),
regexp_substr('Helloworld - test!' ,'[^ - ]+',1,3) from dual;
OUTPUT
col1 col2
Helloworld test!

Answer 3

Trying to negate the match string '[[:space:]]-[[:space:]]' by putting it in a character class with a circumflex (^) to negate it will not work. Everything between a pair of square brackets is treated as a list of optional single characters except for named named character classes which expand out to a list of optional characters, however, due to the way character classes nest, it's very likely that your outer brackets are being interpreted as follows:
[^[[:space:]] A single non space non left square bracket character
- followed by a single hyphen
[[:space:]] followed by a single space character
]+ followed by 1 or more closing square brackets.
It may be easier to convert your multi-character separator to a single character with regexp_replace, then use regex_substr to find you individual pieces:
select regexp_substr(regexp_replace('Helloworld - test!'
,'[[:space:]]-[[:space:]]'
,chr(11))
,'([^'||chr(11)||']*)('||chr(11)||'|$)'
,1 -- Start here
,2 -- return 1st, 2nd, 3rd, etc. match
,null
,1 -- return 1st sub exp
)
from dual;
In this code I first changed - to chr(11). That's the ASCII vertical tab (VT) character which is unlikely to appear in most text strings. Then the match expression of the regexp_substr matches all non VT characters followed by either a VT character or the end of line. Only the non VT characters are returned (the first subexpression).

Answer 4

Slight improvement on MT0's answer. Dynamic count using regexp_count and proves it handles nulls where the format of [^delimiter]+ as a pattern does NOT handle NULL list elements. More info on that here: Split comma seperated values to columns
SQL> with tbl(str) as (
2 select ' - Hello world - test-test! - - test - ' from dual
3 )
4 SELECT LEVEL AS Occurrence,
5 REGEXP_SUBSTR( str ,'(.*?)([[:space:]]-[[:space:]]|$)', 1, LEVEL, NULL, 1 ) AS split_value
6 FROM tbl
7 CONNECT BY LEVEL <= regexp_count(str, '[[:space:]]-[[:space:]]')+1;
OCCURRENCE SPLIT_VALUE
---------- ----------------------------------------
1
2 Hello world
3 test-test!
4
5 test
6
6 rows selected.
SQL>

Answer 5

CREATE OR REPLACE FUNCTION field(i_string VARCHAR2
,i_delimiter VARCHAR2
,i_occurance NUMBER
,i_return_number NUMBER DEFAULT 0
,i_replace_delimiter VARCHAR2) RETURN VARCHAR2 IS
-----------------------------------------------------------------------
-- Function Name.......: FIELD
-- Author..............: Dan Simson
-- Date................: 05/06/2016
-- Description.........: This function is similar to the one I used from
-- long ago by Prime Computer. You can easily
-- parse a delimited string.
-- Example.............:
-- String.............: This is a cool function
-- Delimiter..........: ' '
-- Occurance..........: 2
-- Return Number......: 3
-- Replace Delimiter..: '/'
-- Return Value.......: is/a/cool
-------------------------------------------------------------------------- ---
v_return_string VARCHAR2(32767);
n_start NUMBER := i_occurance;
v_delimiter VARCHAR2(1);
n_return_number NUMBER := i_return_number;
n_max_delimiters NUMBER := regexp_count(i_string, i_delimiter);
BEGIN
IF i_return_number > n_max_delimiters THEN
n_return_number := n_max_delimiters + 1;
END IF;
FOR a IN 1 .. n_return_number LOOP
v_return_string := v_return_string || v_delimiter || regexp_substr (i_string, '[^' || i_delimiter || ']+', 1, n_start);
n_start := n_start + 1;
v_delimiter := nvl(i_replace_delimiter, i_delimiter);
END LOOP;
RETURN(v_return_string);
END field;
SELECT field('This is a cool function',' ',2,3,'/') FROM dual;
SELECT regexp_substr('This is a cool function', '[^ ]+', 1, 1) Word1
,regexp_substr('This is a cool function', '[^ ]+', 1, 2) Word2
,regexp_substr('This is a cool function', '[^ ]+', 1, 3) Word3
,regexp_substr('This is a cool function', '[^ ]+', 1, 4) Word4
,regexp_substr('This is a cool function', '[^ ]+', 1, 5) Word5
FROM dual;