Selecting Distinct does not add DISTINCT to the query

So, with this one:
1. I clone the glossary view
2. Create an attachment display (this is then the second attachment)
3. The attachment has one field (user:name), no arguments, no filters, sort criteria of user:name ascending, and query settings set to distinct
4. The sql result is:
SELECT users.name AS users_name
FROM
{node} node
INNER JOIN {users} users ON node.uid = users.uid
ORDER BY users_name ASC
LIMIT 10 OFFSET 0

5. and the display is
Author
ayen
ayen
ayen
ayen
ayen
ayen
ayen
ayen
ayen
ayen

Below is the export of the additional attachment display. Again, the idea is that the second attachment will provide a list of all authors. The problem is that no permutation of Group By setting and Query Setting: Distinct results in each author name being displayed once, rather than once for every node (in other words, if there are 4 nodes, 2 each for 2 authors, the resulting list has four rows).

/* Display: Attachment */
$handler = $view->new_display('attachment', 'Attachment', 'attachment_1');
$handler->display->display_options['defaults']['query'] = FALSE;
$handler->display->display_options['query']['type'] = 'views_query';
$handler->display->display_options['query']['options']['distinct'] = TRUE;
$handler->display->display_options['pager']['type'] = 'some';
$handler->display->display_options['defaults']['style_plugin'] = FALSE;
$handler->display->display_options['style_plugin'] = 'table';
$handler->display->display_options['style_options']['grouping'] = 'name';
$handler->display->display_options['style_options']['columns'] = array(
'name' => 'name',
);
$handler->display->display_options['style_options']['default'] = 'name';
$handler->display->display_options['style_options']['info'] = array(
'name' => array(
'sortable' => 0,
'default_sort_order' => 'asc',
'align' => '',
'separator' => '',
),
);
$handler->display->display_options['style_options']['override'] = 0;
$handler->display->display_options['style_options']['sticky'] = 0;
$handler->display->display_options['defaults']['style_options'] = FALSE;
$handler->display->display_options['defaults']['row_plugin'] = FALSE;
$handler->display->display_options['defaults']['row_options'] = FALSE;
$handler->display->display_options['defaults']['fields'] = FALSE;
/* Field: User: Name */
$handler->display->display_options['fields']['name']['id'] = 'name';
$handler->display->display_options['fields']['name']['table'] = 'users';
$handler->display->display_options['fields']['name']['field'] = 'name';
$handler->display->display_options['fields']['name']['label'] = 'Author';
$handler->display->display_options['fields']['name']['alter']['alter_text'] = 0;
$handler->display->display_options['fields']['name']['alter']['make_link'] = 1;
$handler->display->display_options['fields']['name']['alter']['path'] = 'author-glossary/all/[name]';
$handler->display->display_options['fields']['name']['alter']['absolute'] = 0;
$handler->display->display_options['fields']['name']['alter']['trim'] = 0;
$handler->display->display_options['fields']['name']['alter']['word_boundary'] = 1;
$handler->display->display_options['fields']['name']['alter']['ellipsis'] = 1;
$handler->display->display_options['fields']['name']['alter']['strip_tags'] = 0;
$handler->display->display_options['fields']['name']['alter']['html'] = 0;
$handler->display->display_options['fields']['name']['element_label_colon'] = 1;
$handler->display->display_options['fields']['name']['element_default_classes'] = 1;
$handler->display->display_options['fields']['name']['hide_empty'] = 0;
$handler->display->display_options['fields']['name']['empty_zero'] = 0;
$handler->display->display_options['fields']['name']['link_to_user'] = 0;
$handler->display->display_options['fields']['name']['overwrite_anonymous'] = 0;
$handler->display->display_options['defaults']['sorts'] = FALSE;
/* Sort criterion: User: Name */
$handler->display->display_options['sorts']['name']['id'] = 'name';
$handler->display->display_options['sorts']['name']['table'] = 'users';
$handler->display->display_options['sorts']['name']['field'] = 'name';
$handler->display->display_options['defaults']['arguments'] = FALSE;
$handler->display->display_options['defaults']['filters'] = FALSE;
$handler->display->display_options['attachment_position'] = 'after';
$handler->display->display_options['inherit_arguments'] = 0;
$handler->display->display_options['displays'] = array(
'page' => 'page',
'default' => 0,
);

I did try another view, and group by nid was present in the query...do not know why it's not in the one above. But that said, I don't understand the intent. If I have one field being displayed, let's say publish date, if I only want one occurrence of each date to be listed, I would choose Distinct, so that the query would be "SELECT DISTINCT publish_date..." I don't see how not having distinct but having Group by nid would be useful.

Will do.