Master SQL for Data Analysis - Conditional Logic – Multiple Rows

The video tutorial covers the use of subqueries in SQL, focusing on conditional logic and multiple row operators like IN, ANY, and ALL. It explains how to use subqueries to filter data, using examples from a book ratings database. The tutorial also discusses alternative methods like inner joins to achieve similar results. Additionally, it demonstrates handling complex queries involving multiple tables, such as filtering books based on user ratings and demographics.

What is the purpose of using the IN operator in a subquery?

• To compare a single value with a set of values returned by the subquery

• To join two tables based on a common attribute

• To update multiple rows in a table

• To delete rows from a table

Which operator can be used as an alternative to IN for subqueries?

• EXISTS

• JOIN

• UPDATE

• DELETE

In the example provided, what is the main purpose of the subquery?

• To delete books with low ratings

• To update the ratings of books

• To find books with an average rating of 9.5

• To list all books published before 2000

What is the key difference between using a subquery and an inner join?

• Inner joins are used to delete data

• Subqueries can only be used with SELECT statements

• Inner joins can combine data from multiple tables directly

• Subqueries are faster than inner joins

What condition is applied to filter books in the inner join example?

• Books published after 2000

• Books with a rating below 5

• Books published before 2000

• Books with no ratings

In the complex query example, what is the first step in the process?

• Select books with a rating above 7

• Create a subquery to list users in the EU over 16

• Join the books and ratings tables

• Update the user information

What is the final step in the complex query example?

• Delete users under 16

• Select the book title for each ISBN

• Join the users and ratings tables

• Update the book ratings