Company: Amazon Senior business research scientist_14april
Difficulty: medium
Question 1 As an Amazon customer service database analyst working on customer profile management, choose the correct explanation of the following query from our system: SELECT * FROM users clients Selects everything in the "users" table, then adds columns from the "clients" table. If the "users" table exists, selects everything from there. Otherwise, queries the "clients" table as a fallback. Selects everything in the "users" table, then assigns the "clients" alias. Selects everything in the "users" table, then adds rows from the "clients" table. Question 2 As an Amazon data analyst examining product category performance metrics, you need to identify problematic SQL queries. Select the expression that causes a MySQL error when analyzing your category database. SELECT AVG( id ) FROM categories SELECT AVG( id ) FROM categories GROUP BY type SELECT 'average', AVG( id ) FROM categories GROUP BY 1 None of the above, all expressions are correct Question 3 As an Amazon customer data analyst,