Min and Max date for Shapefiles return NULL

[anitagraser]

Min and Max date for Shapefiles return NULL. The issue was noted in QGIS (​http://hub.qgis.org/issues/9241).

    $ ogrinfo /tmp/test/test2.shp -sql "SELECT MAX( 'DATE' ) from test2" 
    $ 
    $ INFO: Open of `/tmp/test/test2.shp'
    $   using driver `ESRI Shapefile' successful.
    $ 
    $ Layer name: test2
    $ Geometry: 3D Point
    $ Feature Count: 1
    $ Layer SRS WKT:
    $ (unknown)
    $ MAX_DATE: Date (10.0)
    $ OGRFeature(test2):0
    $   MAX_DATE (Date) = (null)

[Even Rouault]

trunk r26742 : "OGR SQL: implement MIN(), MAX() and AVG() on a date (#5333)"

trunk r26743 : "OGR SQL: Test MIN, MAX and AVG on a date (#5333)"