[ARROW-13190] [C++] [Gandiva] Change behavior of INITCAP function

• Type: New Feature
• Status: Resolved
• Priority: Trivial
• Resolution: Fixed
• Fix Version/s: 5.0.0
• Component/s: C++ - Gandiva
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/28880
• Assignee: Anthony Louis Gotlib Ferreira
• Reporter: Anthony Louis Gotlib Ferreira
• Created: 25/Jun/21 21:36
• Updated: 11/Jan/23 08:31
• Resolved: 15/Jul/21 16:05

Description

The current behavior of the INITCAP function is to turn the first character of each word uppercase and remains the other as is.

The desired behavior is to turn the first letter uppercase and the other lowercase. Any character except the alphanumeric ones should be considered as a word separator. 

That behavior is based on these database systems:

• [Oracle](https://docs.oracle.com/cd/B19306_01/server.102/b14200/functions065.htm)
• [Postgres](https://w3resource.com/PostgreSQL/initcap-function.php)
• [Redshift](https://docs.aws.amazon.com/redshift/latest/dg/r_INITCAP.html)
• [Splice Machine](https://doc.splicemachine.com/sqlref_builtinfcns_initcap.html)

Issue Links

• links to: GitHub Pull Request #10604