Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request.

### Instruction:

Convert text to sql: What is the average rating for each movie that has never been reviewed by Brittany Harris? | movie : mid , title , year , director | reviewer : rid , name | rating : rid , mid , stars , ratingdate | rating.rid = reviewer.rid | rating.mid = movie.mid | 

### Response:

select _ , avg ( _ ) from _ where _ not in ( select _ from _ where _ ) group by _ | select mid , avg ( stars ) from rating where mid not in ( select rating.mid from rating join reviewer on rating.rid = reviewer.rid where reviewer.name = 'Brittany Harris' ) group by mid