Here a non-regex expert with a "poor men's solution" on your challenge;) Find my approach as reference below based on find & mid functionality in attached workbook version 9.3 located in the original thread.
1. Find [: find([ID],"[")
2. Find ]: find([ID],"]")
3. delta: [find ]]]-[find -1
4. ID select: mid([ID],[find +1,[delta])
5. Comment select: mid([ID],1,7)
non-regex_nalmai.twbx 6.8 KB
How to do this will depend on a few factors:
Are you trying to to this in the Database, as custom SQL in tableau or as a calculated field?
What kind of database is it?
How are you connecting to it?
What version of tableau desktop/server are you using?
In the mean time if you just have questions about the regex: RegExr: Learn, Build, & Test RegEx is a fantastic resource for testing regex expressions
So all this data is coming into ms excel file from some 3rd party application,In excel there are millions of rows in form of id's like above mentioned.