Querying null / empty values in complex properties

[pibou_Bouvret]

With such a schema

<ubx_convention:avis>
<item>
<instance>Instance Centrales/Conseil d'administration</instance>
<date>2014-10-09T22:00:00.00Z</date>
</item>
<item>
<instance>Instance opérat/Conseil d'UF xxx</instance>
<date/>
</item>
</ubx_convention:avis>

How can I build a query that returns documents that do not hold at least a void / empty / null date ?

[Florent_Guillau · Accepted solution]

If the only SQL equivalent involves NOT EXISTS then I don't think this can be done in a single query in Nuxeo.