The following are 3 columns that were queried but didn't work:
- timeValue is Null
- booleanvalue Is Not Null
- intKey Is Not Null
The following is the 1 query that did work:
- stringNum Is Not Null
The indexing and querying is implemented via Hibernate Search which sits on top of Lucene. Lucene has no concept of null. Null is emulated by Hibernate Search by using a special (non-null) string marker value (the dreaded null token), but this only works for strings; for other types this fails silently. This limitation cannot be solved with Lucene 3.6 and 4. A better approach might be possible with 5.