Update readme.md

Author: iamAntimPal

LeetCode SQL 50 Solution/1075. Project Employees I/readme.md

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+Here's a well-formatted `README.md` file for your GitHub repository with the SQL solutions:
+
+```md
+# 🏆 Project Employees I - LeetCode 1075
+
+## 📌 Problem Statement
+You are given two tables: **Project** and **Employee**.
+
+### Project Table
+| 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 referencing the `Employee` table.
+
+### Employee Table
+| Column Name      | Type    |
+| ---------------- | ------- |
+| employee_id      | int     |
+| name             | varchar |
+| experience_years | int     |
+
+- `employee_id` is the primary key.
+- `experience_years` is guaranteed to be **NOT NULL**.
+
+The task is to **return the average experience years of all employees for each project, rounded to 2 decimal places**.
+
+---
+
+## 📊 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:
+- **Project 1:** `(3 + 2 + 1) / 3 = 2.00`
+- **Project 2:** `(3 + 2) / 2 = 2.50`
+
+---
+
+## 🖥 SQL Solutions
+
+### 1️⃣ Standard MySQL Solution
+#### Explanation:
+- We **JOIN** the `Project` and `Employee` tables using `employee_id`.
+- We **calculate the average** of `experience_years` for each `project_id`.
+- We **round** the result to **two decimal places**.
+
+```sql
+SELECT project_id, ROUND(AVG(experience_years), 2) AS average_years
+FROM project AS p
+LEFT JOIN employee AS e
+ON p.employee_id = e.employee_id
+GROUP BY project_id;
+```
+
+---
+
+### 2️⃣ Window Function (SQL) Solution
+#### Explanation:
+- Using **window functions**, we calculate the `AVG(experience_years)` over a **partitioned** dataset.
+
+```sql
+SELECT DISTINCT project_id, 
+       ROUND(AVG(experience_years) OVER (PARTITION BY project_id), 2) AS average_years
+FROM project AS p
+JOIN employee AS e 
+ON p.employee_id = e.employee_id;
+```
+
+---
+
+## 🐍 Pandas Solution (Python)
+#### Explanation:
+- We read both tables into Pandas **DataFrames**.
+- We merge the tables on `employee_id`.
+- We group by `project_id` and compute the mean.
+- We round the output to 2 decimal places.
+
+```python
+import pandas as pd
+
+def project_average_experience(project: pd.DataFrame, employee: pd.DataFrame) -> pd.DataFrame:
+    df = project.merge(employee, on="employee_id")
+    result = df.groupby("project_id")["experience_years"].mean().round(2).reset_index()
+    result.columns = ["project_id", "average_years"]
+    return result
+```
+
+---
+
+## 📁 File Structure
+```
+📂 Project-Employees-I
+│── 📜 README.md
+│── 📜 solution.sql
+│── 📜 solution_window.sql
+│── 📜 solution_pandas.py
+│── 📜 test_cases.sql
+```
+
+---
+
+## 🔗 Useful Links
+- 📖 [LeetCode Problem](https://leetcode.com/problems/project-employees-i/)
+- 📚 [SQL Joins Explanation](https://www.w3schools.com/sql/sql_join.asp)
+- 🐍 [Pandas Documentation](https://pandas.pydata.org/docs/)
+```
+
+This README provides:
+- A **clear problem statement**
+- **Input and output tables**
+- **Multiple SQL solutions with explanations**
+- **A Python Pandas solution**
+- **File structure**
+- **Useful links**
+
+Let me know if you need any modifications! 🚀