There are a couple of things to do that I think will help. I will list below:
1. Edit the underlying base view and change the relevant date field to Field Type 'date' instead of 'timestamp'.
2. You can use the function *TO_DATE* for either your input variable or your query date parameter. This date function is listed [here](https://community.denodo.com/docs/html/browse/6.0/vdp/vql/appendix/syntax_of_condition_functions/date_processing_functions#getday).
There is also another thing I would like to bring up: you mentioned timezones, so please note that you can potentially get a different representation of a date field using Virtual DataPort Admin Tool if you use different timezone locales. An excellent read [here](Keep in mind that, as date types include timezone information, you can get a different representation of a date field using VDP admin tool if you use different Locales) goes into how to internationalize date configuration to avoid that potential problem.
Hope this helps!