Counting number of rows returned by a SELECT

How to count the number of rows returned by a select query? The following code throws error "failed to count messages in thread: PGRST200: Could not find a relationship between 'message' and 'COUNT' in the schema cache":
```
var messageCount int64
err = s.supabaseClient.DB.From("message").Select("COUNT(*)").Eq("thread_id", threadID).Execute(&messageCount)
```
