SUNIONSTORE for storing results in Redis - Mini Project: Build & Apply

Using SUNIONSTORE to Combine Sets in Redis

📖 Scenario: You are managing a Redis database for a social app. You have two sets representing users who liked two different posts. You want to create a new set that stores all users who liked either post.

🎯 Goal: Build a Redis command sequence that creates two sets with exact user IDs, then use SUNIONSTORE to combine these sets into a new set storing all unique users who liked either post.

📋 What You'll Learn

Create a Redis set called post1_likes with members user1, user2, and user3

Create a Redis set called post2_likes with members user3, user4, and user5

Use SUNIONSTORE to store the union of post1_likes and post2_likes into a new set called all_likes

Verify the commands use the exact set names and members as specified

💡 Why This Matters

🌍 Real World

Social media apps often track user interactions like likes or follows using sets in Redis for fast membership checks and combining user groups.

💼 Career

Understanding Redis set operations like SUNIONSTORE is important for backend developers working with caching, real-time analytics, and user data aggregation.

1

Create the first set post1_likes

Use the Redis command SADD to create a set called post1_likes with members user1, user2, and user3.

Redis

# Use SADD to add user1, user2, and user3 to post1_likes
# Your code here

Need a hint?

Use SADD followed by the set name and the members separated by spaces.

2

Create the second set post2_likes

Use the Redis command SADD to create a set called post2_likes with members user3, user4, and user5.

Redis

# Use SADD to add user3, user4, and user5 to post2_likes
# Your code here

Need a hint?

Remember to use the exact set name post2_likes and members.

3

Use SUNIONSTORE to combine the sets

Use the Redis command SUNIONSTORE to create a new set called all_likes that stores the union of post1_likes and post2_likes.

Redis

SADD post1_likes user1 user2 user3
SADD post2_likes user3 user4 user5
# Use SUNIONSTORE to store the union of post1_likes and post2_likes into all_likes
# Your code here

Need a hint?

SUNIONSTORE takes the destination set name first, then the source sets.

4

Verify the union set all_likes

Use the Redis command SMEMBERS to check the members of the set all_likes to confirm it contains all unique users from both sets.

Redis

SADD post1_likes user1 user2 user3
SADD post2_likes user3 user4 user5
SUNIONSTORE all_likes post1_likes post2_likes
# Use SMEMBERS to get all members of all_likes
# Your code here

Need a hint?

SMEMBERS returns all members of a set.