Stop redash from converting string to date

I have a string column in my db called calendar_date, which i’m trying to keep as a string. Redash forcibly converts it to a datetime object, which prevents me from using that field as a parameter in a link to another dashboard. I want the format in the link to be YYYY-MM-DD, but redash forces it into something like

https://app.redash.io/ccc1232/public/dashboards/HlFQZ0Ssdfdks9joCFgs2bzv50IKuNx1p54M7Cjz?p_"calendar_date"=Sun%20Jan%2019%202020%2000:00:00%20GMT+0000

How does one get redash to NOT convert strings to dates?

I was able to run a successful test with postgres this way:

select * from (select '2017-06-05' as date_field) temp_table where date_field::text = '{{ date_param }}'

So I can use a URL like this:
https://app.redash.io/ACCOUNT/queries/ID/source?p_date_param=2017-06-05

For this example the important part seems to be the casting the date (using the :: operator in this case): date_field::text, but I’m unclear if that’s just a limitation of the way I quickly created the test data. It might not be necessary to do it this way, but it seems like it ought to work.

https://www.postgresqltutorial.com/postgresql-cast/
https://dev.mysql.com/doc/refman/5.7/en/cast-functions.html