Split records with complex delimiter - regex

Question

I have an incoming record with a complex column delimiter and need to tokenize the record.
One of the delimiter characters can be part of the data.
I am looking for a regex expression.
Required to use on Teradata 16.1 with the function "REGEXP_SUBSTR".
There can max of 5 columns to tokenize.
Planing to use case statements in Teradata to tokenize the columns.
I guess regular expression for one token will do the trick.
Case#1: Column delimiter is ' - '
Sample data: On-e - tw o - thr$ee
Required output : [On-e, tw o, thr$ee]
My attempt : ([\S]*)\s{1}\-{1}\s{1}
Case#2 : Column delimiter is '::'
Sample data : On:e::tw:o::thr$ee
Required output : [On:e, tw:o, thr$ee]
Case#3 : Column delimiter is ':;'
Sample data : On:e:;tw;o:;thr$ee
Required output : [On:e, tw;o, thr$ee]
The above 3 cases are independent and do not occur together ie., 3 different solutions are required

Answer 1

If you absolutely must use RegEx for this, you could do it like in the examples shown below using capture groups.
Generic example:
/(?<data>.+?)($delimiter|$)/gm
(?<data>.+?) named capture group data, matching:
. any character
+? occuring between one and unlimited times
followed by
($delimiter|$) another capture group, matching:
$delimiter - replace this with regex matching your delimiter string
| or
$ end of string
Picking up your examples:
Case #1:
Column delimiter is ' - '
/(?<data>.+?)(\s-\s|$)/gm
(https://regex101.com/r/qMYxAY/1)
Case #2:
Column delimiter is '::'
/(?<data>.+?)(\:\:|$)/gm
https://regex101.com/r/IzaAoA/1
Case #3:
Column delimiter is ':;'
(?<data>.+?)(\:\;|$)
https://regex101.com/r/g1MUb6/1

Answer 2

Normally you would use STRTOK to split a string on a delimiter. But strtok can't handle a multi-character delimiter. One moderately over-complicated approach is to replace the multiple characters of the delimiter with a single character and split on that. For example:
select
strtok(oreplace(<your column>,' - ', '|'),'|',1) as one,
strtok(oreplace(somecol,' - ', '|'),'|',2) as two,
strtok(oreplace(somecol,' - ', '|'),'|',3) as three,
strtok(oreplace(<your column>,' - ', '|'),'|',4) as four,
strtok(oreplace(<your column>,' - ', '|'),'|',5) as five
If there are only three occurrences, like in your samples, it just returns null for the other two.