Master SQL for Data Analysis - Let's Recap

This video tutorial covers key database concepts, starting with creating schemas and loading data. It explores data analysis using operators like UNION, INTERSECT, EXCEPT, and JOIN, and delves into subqueries and CASE statements for complex logic. The tutorial also explains window functions for aggregated calculations and discusses simplifying queries with views and CTEs. The session concludes with a summary and guidance on next steps.

What is the primary purpose of the UNION operator in SQL?

• To find the difference between two tables

• To combine two or more tables into one, removing duplicates

• To find common rows between two tables

• To join tables without any conditions

Which JOIN type is used to select records with matching values in both tables?

• CROSS JOIN

• LEFT JOIN

• FULL OUTER JOIN

• INNER JOIN

What is a key feature of a FULL OUTER JOIN?

• It returns unmatched rows from the left table only

• It returns unmatched rows from the right table only

• It returns all records when there is a match in either left or right table records

• It only returns rows with matching values in both tables

How can subqueries be utilized in SQL?

• To perform data transformation

• To break complex tasks into multiple steps by nesting queries

• To join tables without conditions

• To create virtual tables

What is the purpose of the CASE statement in SQL?

• To perform aggregated calculations

• To join multiple tables

• To simplify queries using CTEs

• To create conditional logic for data transformation

What is a key advantage of using window functions?

• They simplify queries by creating virtual tables

• They are used for data filtering

• They perform aggregated calculations while keeping the original rows

• They allow for data transformation

How do Common Table Expressions (CTEs) benefit SQL queries?

• They break complex queries into separated blocks for better readability

• They perform aggregated calculations

• They are used for data filtering

• They allow for data transformation