SQLSTATE[42S22] error and no results when multiple dates included in views filter

When:

• a filter is added to a view
• the filter is based on multiple date fields
• one or more of the fields comes from the base table (E.g. Node created date for a node view)
• one or more of the fields doesn't come from the base table (E.g. field_data_field_xxxxxxx)

The SQL generated assigns the wrong table to the field that belongs to the base table. E.g. in the example above it will attempt to check field_data_field_xxxxxxx.created which doesn't exist.

This seems to be because of the code in date_views_filter_handler.inc not properly resetting $this->related_table_alias. (Note: The order in which the fields are processed will affect reproducing of this bug since it will only trigger if the base table field is processed after the non-base table field - not sure what controls that?)

Patch to follow.