[rql2sql] when using HAVING to by-pass rql limitation (not to filter on result of an aggregat function), we should emit SQL that doesn't use HAVING to avoid potential backend error because variables are not grouped. Closes #1061603.
Schema of the data
------------------
First take a look at the data schema_ then try to remember that you are browsing
through a heap of data by applying stylesheets to the results of queries. This
site is not a content management system with items placed in folders. It is an
interface to a database which applies a view to retreived data.
.. _schema: schema