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IshaSQL

Foundations Track · Easy · 15 min

Find Followers Count

Table: Followers +-------------+------+ | Column Name | Type | +-------------+------+ | user_id | int | | follower_id | int | +-------------+------+ (user_id...

Foundations Track
Easy
15 min
aggregation

Company labels are directional practice context, not official interview guidance.

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Objective

Practice aggregation through a IshaSQL-tagged business scenario.

Approach

Use this track to lock in clean query structure, basic filtering logic, and confidence with grouped output.

Company context

Company labels are directional practice context, not official interview guidance.

Prereq: query basics
Prereq: filtering

Table: Followers +-------------+------+ | Column Name | Type | +-------------+------+ | user_id | int | | follower_id | int | +-------------+------+ (user_id, follower_id) is the primary key (combination of columns with unique values) for this table. This table contains the IDs of a user and a follower in a social media app where the follower follows the user. Write a solution that will, for each user, return the number of followers. Return the result table ordered by user_id in ascending order. The result format is in the following example. Example 1: Input: Followers table: +---------+-------------+ | user_id | follower_id | +---------+-------------+ | 0 | 1 | | 1 | 0 | | 2 | 0 | | 2 | 1 | +---------+-------------+ Output: +---------+----------------+ | user_id | followers_count| +---------+----------------+ | 0 | 1 | | 1 | 1 | | 2 | 2 | +---------+----------------+ Explanation: The followers of 0 are {1} The followers of 1 are {0} The followers of 2 are {0,1}

Followers
user_id INT
follower_id INT
PRIMARY KEY (user_id
follower_id
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