[ARROW-10115] [C++] CSV empty quoted string is treated as NULL

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.0.1
• Fix Version/s: 5.0.0
• Component/s: C++
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/26128
• Assignee: Antoine Pitrou
• Reporter: Maciej
• Created: 28/Sep/20 12:18
• Updated: 11/Jan/23 08:11
• Resolved: 16/Jun/21 18:05

Description

When parsing my CSV I have set
ConvertOptions::strings_can_be_null to true.

Now as I have values:

1234,"",345

the string value which is an empty string is treated as NULL.
I've checked default valeus of ConvertOptions::null_values and there is empty string considered null, but here we have empty quoted string which shouldn't be treated as NULL in my opinion. Similar behavior we have in Postgresql, empty quoted string is not treated as a NULL: https://www.postgresql.org/docs/12/sql-copy.html

Issue Links

• relates to: ARROW-12510 [C++][Python][CSV] Allow quoted values to be null
• links to: GitHub Pull Request #10503