Now that the user can create and select all the columns of a view, the user can also join on a view.
Let's start with an example android_purchases view.
To grab the user_id column, write the following query:
Now let's take a look at joining the views. The key is to use the square brackets when first referencing the view in the FROM clause, but not when referencing the view when specifying the columns to join on:
The same notation is used for selecting columns that show up in more than one table or view.