No i didn't defined any indexes for the table, I know the performance
will increase with an index, but this was not my question. My question
furthermore belongs to the access mode of the SQL statement.
Furthermore i do not understand why the Upper function should increase
the performance.
The table has approximately 20.000 entries.
Is it the best way to use a B-Tree index on the municipio column in
this case or are there better solution to do this.