[JDO-721] Specifying NULL elements positioning in ordered columns

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: JDO 3 update 1 (3.0.1)
• Fix Version/s: JDO 3.1
• Component/s: specification
• Labels: jdoql
• Assignee: Michael Bouschen
• Reporter: Mohamed Mohsen
• Created: 28/Apr/13 15:59
• Updated: 12/Jun/15 12:53
• Resolved: 19/Oct/14 20:27

Description

I don't know about other RDBMS but in MySQL ordering, it's possible to specify whether NULL column fields are placed in the beginning or at the end of the ordering, i.e.:

ORDER BY `values_column` IS NULL DESC
[values_column]
NULL
NULL
value1
value2
value3

or the other way around (ORDER BY `values_column` IS NULL ASC):
[values_column]
value1
value2
value3
NULL
NULL

I checked JDO 3 specification and found that JDOQL's ordering specification doesn't support specifying NULL values handling:
------------------------------------------------------------------------------
26.7 Ordering Specification
This section describes the syntax of the setOrdering argument.
OrderingClause:
OrderingSpecs ,opt
OrderingSpecs:
OrderingSpec
OrderingSpecs , OrderingSpec
OrderingSpec:
Expression Ascending
Expression Descending
Ascending: one of
asc ascending
Descending: one of
desc descending
Please note, as a usability feature OrderingClause supports an optional trailing comma.
------------------------------------------------------------------------------

Thank you for your time and efforts.