Tableau Prep: Oracle REGEXP Results Differ in Preview and Output

During the design and validation phase, Tableau Prep utilizes a localized Hyper extract to render data previews. 
Conversely, upon flow execution, the application translates regular expression logic into native SQL syntax, delegating the computational workload to the source database for full-scale processing.

Tableau Hyper extracts leverage the International Components for Unicode (ICU) library for regular expression evaluation—a robust open-source standard for C/C++ and Java. 
In contrast, Oracle Database utilizes the POSIX Extended Regular Expression (ERE) standard, augmented by Perl-influenced extensions. 
Consequently, identical patterns may yield disparate results due to these fundamentally different underlying syntactical engines.

To mitigate these discrepancies, use one of the following methods based on your use case 
Option 1: Rewrite the regular expression patterns within POSIX Extended Regular Expression (ERE) standard.
For example:

• Original: REGEXP_MATCH([Category],'^(?:.*?)(Su.*)$')
• Revised: REGEXP_MATCH([Category],'Su')

Option 2: Replace REGEXP functions with string functions.
For example:

• Original: REGEXP_MATCH([Category],'^(?:.*?)(Su.*)$')
• Revised: CONTAINS([Category],'Su')