Hi Stefan,
Unfortunately you can't use a straight qualifier expression for
aggregate functions like MAX, MIN, COUNT. Aside from raw SQL, you may
take a look at this example:
http://objectstyle.org/cayenne/examples/aggregate-functions/index.html
. It shows how you can model special entities just for that purpose.
Examples source code is downloadable separately:
http://objectstyle.org/cayenne/download.html
Hope this helps.
Andrus
On Feb 4, 2004, at 9:57 AM, Stefan Michel wrote:
> I want to query the max value of the column number (Long=BIGINT) in
> table incident .
> I did manage to get this via raw sql using SqlSelectQuery "SELECT
> MAX(number) FROM Incident"
> However would like to get the max value on the object query level.
>
> I want something like this:
> Expression exp=ExpressionFactory.unaryExp(Expression.MAX,
> IncidentImpl.NUMBER_PROPERTY );
> SelectQuery query = new SelectQuery(IncidentImpl.class,exp);
> List data = ctx_.performQuery(query);
> The above gives the following exception
> [java] Caused by: org.postgresql.util.PSQLException: ERROR:
> invalid input syntax for type boolean: "number"
> [java] at
> org.postgresql.util.PSQLException.parseServerError(PSQLException.java:
> 139)
> (number is a Long on obj level - a BIGINT on DB level - getter and
> setter are working- the raw max query is working to)
>
> Does anyone know how to query the max value on an object level ?
>
> The following thread dealt with the same problem, but the proposed
> solution was a raw sql query:
> http://www.objectstyle.org/cayenne/lists/cayenne-user/2003/09/0062.html
>
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