Master SQL for Data Analysis - Overview-3

The video tutorial discusses the common need to combine data from multiple tables in a relational database. It explains how each table stores data on specific entities and may be related to others, necessitating data combination for certain tasks. SQL provides operators like UNION, INTERSECT, and JOIN to facilitate this process. The tutorial introduces these operators and their use cases, focusing on how they help in combining data from various sources.

Why is it often necessary to combine data from multiple tables in a relational database?

• To ensure data redundancy

• To reduce the number of tables in the database

• Because each table stores data on a specific entity type

• To increase the speed of data retrieval

What is the main advantage of using SQL operators to combine data?

• They reduce the size of the database

• They allow for data encryption

• They automatically back up the data

• They provide a way to combine data in various ways

Which of the following is NOT a SQL operator used to combine data?

• UNION

• INTERSECT

• JOIN

• SELECT

What does the UNION operator do in SQL?

• It finds the intersection of two tables

• It selects data from a single table

• It combines rows from two or more tables, removing duplicates

• It joins tables based on a common column

Which SQL operator would you use to find common records between two tables?

• UNION

• INTERSECT

• JOIN

• EXCEPT