Master SQL for Data Analysis - Union, Intersect, Except

The video tutorial covers SQL operators UNION, INTERSECT, and EXCEPT. It explains how UNION combines results from multiple tables, removing duplicates, and provides examples using customer and supplier data. The INTERSECT operator is introduced to find common rows between tables, while the EXCEPT operator is used to find distinct rows in one table that do not appear in another. The tutorial emphasizes the importance of having the same structure in SELECT queries for these operations.

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

• To find rows present in one table but not in another

• To find common rows between two tables

• To combine results from multiple SELECT statements into one table, removing duplicates

• To sort the results of a query

When using the UNION operator, what must be true about the SELECT queries?

• They must have the same number of columns and data types

• They must be from the same database

• They must include a WHERE clause

• They must have different column names

In the example provided, how many distinct cities were found using the UNION operator?

• 7

• 162

• 161

• 6

What does the INTERSECT operator do in SQL?

• Finds rows present in one table but not in another

• Combines results from multiple SELECT statements into one table

• Sorts the results of a query

• Finds common rows between two tables

How many cities were found to exist in both the customer and supplier tables using the INTERSECT operator?

• 7

• 161

• 6

• 162

What is the purpose of the EXCEPT operator in SQL?

• To find rows present in one table but not in another

• To find common rows between two tables

• To combine results from multiple SELECT statements into one table

• To sort the results of a query

In the EXCEPT example, how many distinct cities were found in the customers table but not in the suppliers table?

• 162

• 161

• 155

• 6