I have a requirement to create a function which will check if the same alphabet occurrence is more than 2 it will raise an error. Any help
As the forum title says this forum is ONLY for sql developer questions.
If you have a requirement to 'create a function' then your manager wants you to go to your computer and write the function. Why are you posting here? This is NOT a coding service. The forums are to help you with YOUR code.
Why would your manager give you that assignement unless you know how to write the function? If you don't know how to write such a function you should tell your manager right away so they can assign someone else to do it.
After you write the function you need to test it. Then if you run into any issues with it create a new thread in the SQL and PL/SQL forum and post your question there.