DISTINCT

🎬 Scenario: Finding Unique Subscription Plans

Your manager at Netflix, Alex, is analyzing customer trends and wants to know which unique subscription plans are currently active.

Alex asks:

Can you provide a list of all the different subscription plans that exist in our database?

Your task is to query the netflix_users table and provide the requested data.

Removing Duplicates with DISTINCT

By default, when you SELECT a column, SQL returns all records, even if some values repeat. The DISTINCT keyword removes duplicate values, ensuring that each unique value appears only once.

Syntax:

1SELECT DISTINCT column_name  
2FROM table_name;

Example Query: Finding Unique Subscription Plans

1SELECT DISTINCT subscription_plan  
2FROM netflix_users;

Expected Output:

What’s Happening?

• The DISTINCT keyword removes duplicate subscription plans from the result set.
• Instead of listing every user’s plan, we get a concise summary of all available options.

Using DISTINCT with Multiple Columns

We can also apply DISTINCT to multiple columns, ensuring unique combinations of values are returned.

Example Query: Finding Unique Subscription Plans by Country

1SELECT DISTINCT subscription_plan, country  
2FROM netflix_users;

Expected Output:

What’s Happening?

• The query ensures that each combination of subscription_plan and country appears only once.

✍️ SQL Exercises

Exercise 1: Identifying Countries with Netflix Users

Netflix wants to identify all unique countries where users have signed up.

Filter condition:

• Retrieve a distinct list of country values from the netflix_users table.

Expected Output:

Write an SQL query to return the requested data.

Exercise 2: Finding Unique Watch History Entries

Netflix’s data team wants to know the different combinations of users and series they have watched to understand viewer engagement. Sort the table based on the ascending order of user_id and series_id

Filter condition:

• Retrieve unique pairs of user_id and series_id from the watch_history table.

Expected Output:

Write an SQL query to return the requested data.