Oracle Solution for Error ora-06504

ORA-06504: PL/SQL: Return types of Result Set variables or query do not match

What triggered the Error:

Number and/or types of columns in a query does not match declared return type of a result set variable, or declared types of two Result Set variables do not match.

What should we do to fix it:

Change the program statement or declaration. Verify what query the variable actually refers to during execution.