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Hibernate version:
3.0.3

How to use named queries with potential nullable columns/values?
e.g.

<query ...
and a.mycol = :mycolval
</query>

At runtime there are some possibilities:
1. mycolval != null
2. mycolval == null
3. mycolval == (empty string)

for 1. the named query works fine
for 2. (and possibly 3), the named query is wrong (s/be a.mycol is null)

Is their any elegant solution using named queries?
Thanks.

try

<query ...
and (a.mycol is null or a.mycol = :mycolval)
</query>

thanks for the reply - but I need matching values in this case (I only want null's if mycolval == null).

I would use Criteria as follows:

if(obj == null) criteria.add(Restrictions.isNull(mycol));
else criteria.add(Restrictions.eg(mycol, obj));

???

however I can't figure out using this criteria with an aggregate select

eg

'select max(t.num) from table t' --> + above Criteria

I use named queries often and they're great. But they're not for everything.

This is one such case. Stick with the criteria.