Master SQL for Data Analysis - Distinct Values (DISTINCT)

The video tutorial explains how to use the SQL SELECT DISTINCT statement to find unique values in data columns. It covers the basic syntax, handling null values, and using DISTINCT with multiple columns. Additionally, it demonstrates combining DISTINCT with aggregation functions like COUNT to analyze data effectively.

What is the primary purpose of using the SELECT DISTINCT statement in SQL?

• To delete null values from a table

• To sort the data in ascending order

• To return only unique values from a column

• To find duplicate values in a column

How can you modify a SELECT DISTINCT query to exclude null values?

• By using the ORDER BY clause

• By adding a WHERE condition to filter out nulls

• By using the GROUP BY clause

• By using the HAVING clause

What will be the result of using SELECT DISTINCT with two columns?

• It will return the sum of the two columns

• It will return only the first column's unique values

• It will return unique pairs of values from the two columns

• It will return all rows from the table

In which scenario would you use DISTINCT inside an aggregate function like COUNT?

• When you want to count only unique values in a column

• When you want to count all rows in a table

• When you want to find the maximum value in a column

• When you want to sum all values in a column

What is a common use case for combining COUNT and DISTINCT in SQL?

• To list all values in a column

• To count the number of unique entries in a column

• To find the average of all values in a column

• To delete duplicate entries from a table