[SOLVED] : Group by having causes "inner hasNext was false" error

[Bertrand Delacretaz <bd...@apache.org>]

Le 12 sept. 05 à 17:37, Bertrand Delacretaz a écrit :

> ...I'm using a GROUP BY HAVING query (using addGroupBy and  
> setHavingCriteria to a QueryByCriteria), and depending on the data  
> I get an "inner hasNext was false" error.

> IIUC the problem is due to the SELECT COUNT [2] query used by OJB  
> to find out how many objects to retrieve, which in some cases finds  
> more objects that the main query retrieves, causing the RsIterator  
> to fail as it believes there are more objects to retrieve but finds  
> the end of the result set...

I went back to this old problem, and fixed it simply by specifiying  
that my MySQL driver is JDBC 3.0 capable, by adding

     <jdbc-connection-descriptor ... jdbc-level="3.0">

in my ojb-repository.xml

Without this, OJB does a SELECT COUNT request to get the size of the  
result set, and the generated SELECT was incorrect when my main query  
includes a HAVING count(*) >= N clause.

Debugging the RsIterator class allowed me to see exactly what was  
happening and fix my (stupid) mistake.

Just thought I'd send this info here so that others might be spared  
the pain ;-)

-Bertrand