Issue 51538

I talked with Mechtilde and now I see the problem. This behaviour occurs, if you
select fields from different tables in step 1 of the wizard. Its seems to be the
problem, that the wizard does not "know" the relation between both tables. It
seems, that OOo tries to run the query, but (certainly!) gets no result.

I tried it with a postgresql per odbc and I couldn't define a relation (I think,
the odbc driver doesn't support it). But we had an example, that there was a
defined relation (I can't reproduce it) where there was a defined relation, but
it didn't make a difference for the query wizard. 

In my opinion the behaviour is not really a bug (exept a missing significant
error message), rather a enhancement for the wizard.

The "easy solution" for this problem would be:
- The wizard should give a error message if fields from different tables are
selected or should not allow field-selection from different tables at all

The "nice solution":
- The wizard should take into account, if there are already defined relations
- The wizard should allow to define relations in a separate step

accepting as enhancement.

The current behaviour might cause heavy troubles, if you select field from
different tables with a high amount of data. this might even lead to a
DB-freeze, if data are retrieved right after creating the query.

I agree, that there at least should be a warning.

Competitive analysis:
MS Access (XP) uses predefined relations between tables. It even respects
"chained relations" (table1 -> table2 -> table3) if not all tables in the chain
are in defined fieldlist.