How can I get the complete query? I am displaying a Drupal 8 view. I see that all of the fields that are displayed in the view are not in the query.

How does this work?
For query tracing you can use devel module. Devel module include the Web Profiler module which shows many options. Even you can see the all queries executed for page.

Following are the sample details of web profiler. 



UPDATE: So how you can see your view query in web profiler?
Well, follow this steps.


For tracing purpose disable view cache. "Select 'No Cache' from advance section".
Then Clear all drupal cache.
Open views output page.
Click on database link from web profiler.
Now search in page(Ctr+F) your field name.
E.g: Here I added one field in my view, that is field_image. So I search that and I get view query..
Once you found out your query, you will see there is no parameter in query, Well to see which paraters query is taking click on "Info" tab of query. And you will see all parameters of placeholder.