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IshaSQL

Interview Core Track · Easy · 15 min

Project Employees I

Table: Project +-------------+---------+ | Column Name | Type | +-------------+---------+ | project_id | int | | employee_id | int | +-------------+---------...

Interview Core Track
Easy
15 min
joins
aggregation

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

Timer 00:00
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Objective

Practice joins through a IshaSQL-tagged business scenario.

Approach

Use this track to improve speed, edge-case handling, and accuracy under timed conditions.

Company context

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

Prereq: query basics
Prereq: filtering

Table: Project +-------------+---------+ | Column Name | Type | +-------------+---------+ | project_id | int | | employee_id | int | +-------------+---------+ (project_id, employee_id) is the primary key of this table. employee_id is a foreign key to Employee table. Each row of this table indicates that the employee with employee_id is working on the project with project_id. Table: Employee +------------------+---------+ | Column Name | Type | +------------------+---------+ | employee_id | int | | name | varchar | | experience_years | int | +------------------+---------+ employee_id is the primary key of this table. It's guaranteed that experience_years is not NULL. Each row of this table contains information about one employee. Write an SQL query that reports the average experience years of all the employees for each project, rounded to 2 digits . Return the result table in any order . The query result format is in the following example. Example 1: Input: Project table: +-------------+-------------+ | project_id | employee_id | +-------------+-------------+ | 1 | 1 | | 1 | 2 | | 1 | 3 | | 2 | 1 | | 2 | 4 | +-------------+-------------+ Employee table: +-------------+--------+------------------+ | employee_id | name | experience_years | +-------------+--------+------------------+ | 1 | Khaled | 3 | | 2 | Ali | 2 | | 3 | John | 1 | | 4 | Doe | 2 | +-------------+--------+------------------+ Output: +-------------+---------------+ | project_id | average_years | +-------------+---------------+ | 1 | 2.00 | | 2 | 2.50 | +-------------+---------------+ Explanation: The average experience years for the first project is (3 + 2 + 1) / 3 = 2.00 and for the second project is (3 + 2) / 2 = 2.50

Project
project_id INT
employee_id INT
PRIMARY KEY (project_id
employee_id
Employee
employee_id INT PRIMARY KEY
name VARCHAR(100
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