问题 I created a product / review system from scratch and I´m having a hard time to do the following query in SQL Server. My schema has different tables, for: products, reviews, categories, productPhotos and Brand. I have to query them all to find the brand and category name, photos details, Average Rating and Number of Reviews. I´m having a hard time to get No. of reviews and average rating. Reviews can be hidden (user has deleted) or blocked (waiting for moderation). My product table doesn't