SQL CHEAT SHEET - Save This!
Most Asked SQL in Tech Interviews!
====================================
SQL is tested in 90% of tech interviews!
TCS, Infosys, Amazon, Flipkart, Data Analyst
roles ALL require strong SQL. Master this!
====================================
BASIC QUERIES
SELECT * FROM employees;
-> Get all rows from table
SELECT name, salary FROM employees
WHERE salary > 50000;
-> Filter rows with condition
SELECT * FROM employees
ORDER BY salary DESC LIMIT 5;
-> Top 5 highest paid employees
SELECT DISTINCT department FROM employees;
-> Get unique departments only
====================================
AGGREGATE FUNCTIONS
SELECT COUNT(*) FROM employees;
-> Total number of rows
SELECT AVG(salary) FROM employees;
-> Average salary
SELECT MAX(salary), MIN(salary) FROM employees;
-> Highest and lowest salary
SELECT department, COUNT(*) as emp_count
FROM employees
GROUP BY department
HAVING COUNT(*) > 5;
-> Departments with more than 5 employees
====================================
JOINS - Most Asked in Interviews!
INNER JOIN - Only matching rows in both tables:
SELECT e.name, d.dept_name
FROM employees e
INNER JOIN departments d ON e.dept_id = d.id;
LEFT JOIN - All from left + matching right:
SELECT e.name, d.dept_name
FROM employees e
LEFT JOIN departments d ON e.dept_id = d.id;
SELF JOIN - Table joined with itself:
SELECT e1.name, e2.name AS manager
FROM employees e1
JOIN employees e2 ON e1.manager_id = e2.id;
====================================
SUBQUERIES - Asked in Advanced Rounds!
Employees earning more than average:
SELECT name FROM employees
WHERE salary > (SELECT AVG(salary) FROM employees);
2nd highest salary (Classic Question!):
SELECT MAX(salary) FROM employees
WHERE salary < (SELECT MAX(salary) FROM employees);
Nth highest salary using LIMIT:
SELECT salary FROM employees
ORDER BY salary DESC LIMIT 1 OFFSET N-1;
====================================
WINDOW FUNCTIONS - Modern SQL!
Rank employees by salary:
SELECT name, salary,
RANK() OVER (ORDER BY salary DESC) as rnk
FROM employees;
Row number within each department:
SELECT name, department,
ROW_NUMBER() OVER
(PARTITION BY department ORDER BY salary DESC)
FROM employees;
====================================
TOP 5 SQL INTERVIEW QUESTIONS:
1. Find duplicate records in a table
2. Find employees with no manager (NULL)
3. Find departments with zero employees
4. Find Nth highest salary
5. Difference between WHERE and HAVING?
====================================
PRACTICE FREE ON:
SQLZoo -> sqlzoo.net
HackerRank -> hackerrank.com/domains/sql
LeetCode -> leetcode.com/problemset/database
====================================
Save this before your next interview!
Get FREE projects with database code:
https://t.me/Projectwithsourcecodes
Share with your placement batch!
#SQLCheatSheet #SQL #MySQL #PostgreSQL
#DatabaseInterview #Joins #Subqueries #WindowFunctions
#BTech2026 #MCA2026 #BCA2026 #PlacementPrep
#DataAnalyst #BackendDeveloper #TechInterview
#ProjectWithSourceCodes #StudentsOfIndia
Most Asked SQL in Tech Interviews!
====================================
SQL is tested in 90% of tech interviews!
TCS, Infosys, Amazon, Flipkart, Data Analyst
roles ALL require strong SQL. Master this!
====================================
BASIC QUERIES
SELECT * FROM employees;
-> Get all rows from table
SELECT name, salary FROM employees
WHERE salary > 50000;
-> Filter rows with condition
SELECT * FROM employees
ORDER BY salary DESC LIMIT 5;
-> Top 5 highest paid employees
SELECT DISTINCT department FROM employees;
-> Get unique departments only
====================================
AGGREGATE FUNCTIONS
SELECT COUNT(*) FROM employees;
-> Total number of rows
SELECT AVG(salary) FROM employees;
-> Average salary
SELECT MAX(salary), MIN(salary) FROM employees;
-> Highest and lowest salary
SELECT department, COUNT(*) as emp_count
FROM employees
GROUP BY department
HAVING COUNT(*) > 5;
-> Departments with more than 5 employees
====================================
JOINS - Most Asked in Interviews!
INNER JOIN - Only matching rows in both tables:
SELECT e.name, d.dept_name
FROM employees e
INNER JOIN departments d ON e.dept_id = d.id;
LEFT JOIN - All from left + matching right:
SELECT e.name, d.dept_name
FROM employees e
LEFT JOIN departments d ON e.dept_id = d.id;
SELF JOIN - Table joined with itself:
SELECT e1.name, e2.name AS manager
FROM employees e1
JOIN employees e2 ON e1.manager_id = e2.id;
====================================
SUBQUERIES - Asked in Advanced Rounds!
Employees earning more than average:
SELECT name FROM employees
WHERE salary > (SELECT AVG(salary) FROM employees);
2nd highest salary (Classic Question!):
SELECT MAX(salary) FROM employees
WHERE salary < (SELECT MAX(salary) FROM employees);
Nth highest salary using LIMIT:
SELECT salary FROM employees
ORDER BY salary DESC LIMIT 1 OFFSET N-1;
====================================
WINDOW FUNCTIONS - Modern SQL!
Rank employees by salary:
SELECT name, salary,
RANK() OVER (ORDER BY salary DESC) as rnk
FROM employees;
Row number within each department:
SELECT name, department,
ROW_NUMBER() OVER
(PARTITION BY department ORDER BY salary DESC)
FROM employees;
====================================
TOP 5 SQL INTERVIEW QUESTIONS:
1. Find duplicate records in a table
2. Find employees with no manager (NULL)
3. Find departments with zero employees
4. Find Nth highest salary
5. Difference between WHERE and HAVING?
====================================
PRACTICE FREE ON:
SQLZoo -> sqlzoo.net
HackerRank -> hackerrank.com/domains/sql
LeetCode -> leetcode.com/problemset/database
====================================
Save this before your next interview!
Get FREE projects with database code:
https://t.me/Projectwithsourcecodes
Share with your placement batch!
#SQLCheatSheet #SQL #MySQL #PostgreSQL
#DatabaseInterview #Joins #Subqueries #WindowFunctions
#BTech2026 #MCA2026 #BCA2026 #PlacementPrep
#DataAnalyst #BackendDeveloper #TechInterview
#ProjectWithSourceCodes #StudentsOfIndia
HackerRank
Solve Programming Questions | HackerRank
A special-purpose language designed for managing data held in a relational database.
HOSTEL MANAGEMENT SYSTEM - PHP & MySQL
Final Year Project with Full Source Code!
Role-based web app for colleges to manage
hostel registration, room allocation, complaints
and messaging. Perfect for BCA/MCA/BTech!
#FinalYearProject #PHP #MySQL #SourceCode
#BTech2026 #MCA2026 #BCA2026
#ProjectWithSourceCodes #StudentsOfIndia
Final Year Project with Full Source Code!
Role-based web app for colleges to manage
hostel registration, room allocation, complaints
and messaging. Perfect for BCA/MCA/BTech!
#FinalYearProject #PHP #MySQL #SourceCode
#BTech2026 #MCA2026 #BCA2026
#ProjectWithSourceCodes #StudentsOfIndia
HOSTEL MANAGEMENT SYSTEM
PHP + MySQL | Final Year Project
====================================
A role-based web application for colleges to manage hostel
registration, room allocation, complaint handling and internal
communication between students, managers and admins.
KEY FEATURES:
- User registration & role-based login
- Student hostel application workflow
- Room allocation & vacancy management
- Complaint submission & status tracking
- Internal messaging (student <-> manager)
- Full admin control panel
USER ROLES:
- Admin: manages hostels, rooms, users, applications, complaints
- Manager: reviews applications, allocates rooms, handles complaints
- Student: applies for hostel, tracks room, raises complaints
TECH STACK:
- PHP (procedural, MySQLi)
- MySQL database
- HTML, CSS, JavaScript
- Runs on XAMPP / WAMP / LAMP
WHAT YOU GET:
- Complete source code
- Documentation
- Easy installer (install.php) + demo accounts
- Support
====================================
DOWNLOAD / BUY THIS PROJECT:
https://updategadh.com/hostel-management-system-php-and-mysql/
More ready-made projects with source code:
https://t.me/Projectwithsourcecodes
Share with your final-year batch!
#FinalYearProject #PHP #MySQL #WebDevelopment
#HostelManagement #SourceCode #DBMS #MiniProject
#BTech2026 #MCA2026 #BCA2026
#ProjectWithSourceCodes #StudentsOfIndia
PHP + MySQL | Final Year Project
====================================
A role-based web application for colleges to manage hostel
registration, room allocation, complaint handling and internal
communication between students, managers and admins.
KEY FEATURES:
- User registration & role-based login
- Student hostel application workflow
- Room allocation & vacancy management
- Complaint submission & status tracking
- Internal messaging (student <-> manager)
- Full admin control panel
USER ROLES:
- Admin: manages hostels, rooms, users, applications, complaints
- Manager: reviews applications, allocates rooms, handles complaints
- Student: applies for hostel, tracks room, raises complaints
TECH STACK:
- PHP (procedural, MySQLi)
- MySQL database
- HTML, CSS, JavaScript
- Runs on XAMPP / WAMP / LAMP
WHAT YOU GET:
- Complete source code
- Documentation
- Easy installer (install.php) + demo accounts
- Support
====================================
DOWNLOAD / BUY THIS PROJECT:
https://updategadh.com/hostel-management-system-php-and-mysql/
More ready-made projects with source code:
https://t.me/Projectwithsourcecodes
Share with your final-year batch!
#FinalYearProject #PHP #MySQL #WebDevelopment
#HostelManagement #SourceCode #DBMS #MiniProject
#BTech2026 #MCA2026 #BCA2026
#ProjectWithSourceCodes #StudentsOfIndia
🎟 <b>EVENTRA — Event Management System</b>
<i>PHP + MySQL | Final Year Project</i>
A complete campus event booking platform with a modern UI, QR tickets and a full admin dashboard.
━━━━━━━━━━━━━━━━━━
👨🎓 <b>USER PANEL</b>
✅ Browse events with search, category filters & sorting
✅ One-click seat booking
✅ <b>QR code tickets</b> (printable)
✅ Cancel bookings & free the seat instantly
✅ Rate and review events you attended
✅ Email confirmation on every booking
✅ Profile + password management
🛠 <b>ADMIN PANEL</b>
✅ Dashboard with live stats & revenue charts
✅ Analytics — bookings, revenue, top venues
✅ Full CRUD: Events, Venues, Users, Bookings
✅ Event poster upload
✅ Review moderation
✅ Role management (suspend / promote users)
━━━━━━━━━━━━━━━━━━
🔐 <b>SECURITY DONE RIGHT</b>
🛡 SQL Injection safe — 100% prepared statements
🛡 Bcrypt password hashing
🛡 CSRF protection on every form
🛡 Role-based access control
🛡 XSS-safe output escaping
💻 <b>TECH STACK</b>
<code>PHP 8.1</code> • <code>MySQL / MariaDB</code> • <code>Custom CSS</code> • <code>Vanilla JS</code>
⚡️ <b>Zero dependencies.</b> No Composer, no CDN, no framework.
Works 100% offline on XAMPP.
🌗 Dark mode + fully responsive (mobile → desktop)
━━━━━━━━━━━━━━━━━━
📦 <b>What you get:</b>
Full source code • Database file • README with setup guide
🔗 <b>Download:</b> https://updategadh.com
#PHP #MySQL #FinalYearProject #WebDevelopment #EventManagement #BCA #MCA #BTech
5 LATEST FINAL YEAR PROJECTS - UPDATEGADH
With Full Source Code + Documentation
====================================
1. Railway Management System - PHP & MySQL
Book, manage & track trains - a classic, impressive DBMS project
https://updategadh.com/railway-management-system-in-php-and-mysql/
2. Agentic RAG AI System - Python
Advanced 2026 AI architecture - build your own agentic RAG system
https://updategadh.com/agentic-rag-ai-system-using-python/
3. AI Online Examination System with Face Detection - PHP & MySQL
Secure online exams with AI proctoring & face detection
https://updategadh.com/online-examination-system-with-face-detection/
4. Real-Time Medical Queue & Appointment System - Django
MediQueue - live patient queue & appointment booking
https://updategadh.com/appointment-system-with-django/
5. Online Examination System - PHP
Complete exam portal for BCA/MCA/B.Tech/M.Tech with source code
https://updategadh.com/online-examination-system-in-php-with-source-code/
====================================
Each project includes:
- Complete source code
- Documentation
- Setup guide & support
====================================
More ready-made projects with source code:
https://t.me/Projectwithsourcecodes
Share with your final-year batch!
#FinalYearProject #SourceCode #PHP #MySQL #Python
#Django #AI #RAG #DBMS #WebDevelopment #MiniProject
#BTech2026 #MCA2026 #BCA2026
#ProjectWithSourceCodes #StudentsOfIndia
With Full Source Code + Documentation
====================================
1. Railway Management System - PHP & MySQL
Book, manage & track trains - a classic, impressive DBMS project
https://updategadh.com/railway-management-system-in-php-and-mysql/
2. Agentic RAG AI System - Python
Advanced 2026 AI architecture - build your own agentic RAG system
https://updategadh.com/agentic-rag-ai-system-using-python/
3. AI Online Examination System with Face Detection - PHP & MySQL
Secure online exams with AI proctoring & face detection
https://updategadh.com/online-examination-system-with-face-detection/
4. Real-Time Medical Queue & Appointment System - Django
MediQueue - live patient queue & appointment booking
https://updategadh.com/appointment-system-with-django/
5. Online Examination System - PHP
Complete exam portal for BCA/MCA/B.Tech/M.Tech with source code
https://updategadh.com/online-examination-system-in-php-with-source-code/
====================================
Each project includes:
- Complete source code
- Documentation
- Setup guide & support
====================================
More ready-made projects with source code:
https://t.me/Projectwithsourcecodes
Share with your final-year batch!
#FinalYearProject #SourceCode #PHP #MySQL #Python
#Django #AI #RAG #DBMS #WebDevelopment #MiniProject
#BTech2026 #MCA2026 #BCA2026
#ProjectWithSourceCodes #StudentsOfIndia
UpdateGadh Store
Buy Visitor Management System PHP Source Code
Download Visitor Management System in PHP with source code, admin & guard panels, visitor check-in/check-out tracking and full setup guide.
🛂 VISITOR MANAGEMENT SYSTEM — PHP Project
A lightweight web app for tracking who's coming in and out of your organization — built for security desks and front offices. Here's what's inside 👇
🛠️ ADMIN SECTION
• Employee & department management
• View + filter visitor logs by date
• Generate visitor activity reports
• Manage guard/receptionist user accounts
👮 GUARD (USER) SECTION
• Quick visitor check-in & check-out
• Fast, simple data entry — no clutter
✅ WHY IT'S USEFUL
• Clean, intuitive interface for both admin & guard
• All records organized — employees, departments, visitors
• Role-based access keeps data secure
• Reports make security analysis & planning easier
⚙️ STACK
PHP · MySQL · CSS · Runs on XAMPP
🎓 GOOD FOR
Front-desk security systems, college/final-year projects, or anyone wanting a simple real-world example of role-based (admin vs guard) access control.
🔥 50% OFF right now on the source code!
🛒 Grab it here: https://store.updategadh.com/product/visitor-management-system-in-php/
🔗 Full write-up: https://updategadh.com/visitor-management-system-in-php/
💬 Would your office benefit from something like this? Let us know 👇
#PHPProject #VisitorManagementSystem #WebDevelopment #FinalYearProject #MySQL
A lightweight web app for tracking who's coming in and out of your organization — built for security desks and front offices. Here's what's inside 👇
🛠️ ADMIN SECTION
• Employee & department management
• View + filter visitor logs by date
• Generate visitor activity reports
• Manage guard/receptionist user accounts
👮 GUARD (USER) SECTION
• Quick visitor check-in & check-out
• Fast, simple data entry — no clutter
✅ WHY IT'S USEFUL
• Clean, intuitive interface for both admin & guard
• All records organized — employees, departments, visitors
• Role-based access keeps data secure
• Reports make security analysis & planning easier
⚙️ STACK
PHP · MySQL · CSS · Runs on XAMPP
🎓 GOOD FOR
Front-desk security systems, college/final-year projects, or anyone wanting a simple real-world example of role-based (admin vs guard) access control.
🔥 50% OFF right now on the source code!
🛒 Grab it here: https://store.updategadh.com/product/visitor-management-system-in-php/
🔗 Full write-up: https://updategadh.com/visitor-management-system-in-php/
💬 Would your office benefit from something like this? Let us know 👇
#PHPProject #VisitorManagementSystem #WebDevelopment #FinalYearProject #MySQL
UpdateGadh Store
Online Bike Rental Management System PHP | UpdateGadh
🏍️ ONLINE BIKE RENTAL MANAGEMENT SYSTEM — PHP Project
A complete web platform for renting bikes online — bike listings, user accounts, rentals & payments, all in one system. Here's what's inside 👇
🛠️ ADMIN SECTION
• Secure admin login
• Add, update & remove bike listings
• View & manage registered users
• Track & manage bike rentals
• Monitor payment records
🚴 USER SECTION
• Registration & login
• Profile management
• Browse available bikes
• Rent bikes in a few clicks
• View rental history & transactions
• Make payments & track payment status
⚙️ STACK
PHP · MySQL · Bootstrap · HTML/CSS/JS · AJAX/jQuery · Runs on XAMPP/WAMP/LAMP
🎓 GOOD FOR
BCA, MCA, B.Tech CS/IT students & developers who want a real example of user management, rentals, and payment tracking in a database-driven web app — great as an academic or portfolio project.
📦 What you get: Source Code + Database + Project Report + PPT + Viva Questions + Setup Guide
🛒 Grab it here: https://store.updategadh.com/product/bike-rental-management-system/
🔗 Full write-up: https://updategadh.com/bike-rental-management-system/
💬 Ever rented a bike online? Would you build something like this? 👇
#PHPProject #BikeRentalSystem #WebDevelopment #FinalYearProject #MySQL
A complete web platform for renting bikes online — bike listings, user accounts, rentals & payments, all in one system. Here's what's inside 👇
🛠️ ADMIN SECTION
• Secure admin login
• Add, update & remove bike listings
• View & manage registered users
• Track & manage bike rentals
• Monitor payment records
🚴 USER SECTION
• Registration & login
• Profile management
• Browse available bikes
• Rent bikes in a few clicks
• View rental history & transactions
• Make payments & track payment status
⚙️ STACK
PHP · MySQL · Bootstrap · HTML/CSS/JS · AJAX/jQuery · Runs on XAMPP/WAMP/LAMP
🎓 GOOD FOR
BCA, MCA, B.Tech CS/IT students & developers who want a real example of user management, rentals, and payment tracking in a database-driven web app — great as an academic or portfolio project.
📦 What you get: Source Code + Database + Project Report + PPT + Viva Questions + Setup Guide
🛒 Grab it here: https://store.updategadh.com/product/bike-rental-management-system/
🔗 Full write-up: https://updategadh.com/bike-rental-management-system/
💬 Ever rented a bike online? Would you build something like this? 👇
#PHPProject #BikeRentalSystem #WebDevelopment #FinalYearProject #MySQL
https://updategadh.com/
Railway Management System in PHP and MySQL
Railway Management System in PHP and MySQL is one of the best ways to master real-world CRUD (Create, Read, Update, Delete) applications
🚆 Railway Management System in PHP & MySQL
Looking for a Railway Management System project in PHP and MySQL? This complete project is useful for students and developers who want to understand railway reservation and management functionality.
✨ Features:
✅ Train Management
✅ Ticket Booking & Reservation
✅ Passenger Management
✅ Train Schedule Management
✅ User/Admin Login
✅ PHP & MySQL Database
✅ Easy-to-understand project structure
👉 Read the Complete Project:
Railway Management System in PHP & MySQL
#PHP #MySQL #RailwayManagementSystem #PHPProject #MySQLProject #StudentProject #WebDevelopment
Looking for a Railway Management System project in PHP and MySQL? This complete project is useful for students and developers who want to understand railway reservation and management functionality.
✨ Features:
✅ Train Management
✅ Ticket Booking & Reservation
✅ Passenger Management
✅ Train Schedule Management
✅ User/Admin Login
✅ PHP & MySQL Database
✅ Easy-to-understand project structure
👉 Read the Complete Project:
Railway Management System in PHP & MySQL
#PHP #MySQL #RailwayManagementSystem #PHPProject #MySQLProject #StudentProject #WebDevelopment
UpdateGadh Store
Buy Flipkart Clone in PHP MySQL Source Code | UpdateGadh
Download Flipkart Clone in PHP and MySQL with complete source code, admin panel, cart, checkout and order tracking. Includes database, report and PPT.
🛒 Flipkart Clone using PHP & MySQL! 🚀
A complete E-Commerce Website Project with product management, shopping cart, orders, user login & more. 💻🔥
🛍️ Buy Project: https://store.updategadh.com/product/flipkart-clone/
🔗 Project Details: https://updategadh.com/flipkart-clone/
#FlipkartClone #PHP #MySQL #PHPProject #EcommerceWebsite #WebDevelopment #FinalYearProject #Coding
A complete E-Commerce Website Project with product management, shopping cart, orders, user login & more. 💻🔥
🛍️ Buy Project: https://store.updategadh.com/product/flipkart-clone/
🔗 Project Details: https://updategadh.com/flipkart-clone/
#FlipkartClone #PHP #MySQL #PHPProject #EcommerceWebsite #WebDevelopment #FinalYearProject #Coding
https://updategadh.com/
Advance Employee Management System Using PHP and MySQL
The Advance Employee Management System Using PHP and MySQL is a web-based employee management solution developed using PHP and
🚀 Advance Employee Management System Using PHP & MySQL
A complete HR & Employee Management System built with PHP and MySQL! 💻
🔥 Key Features:
✅ Employee & Department Management
✅ Face Recognition Attendance
✅ Attendance & Leave Management
✅ Payroll Management
✅ Task Management
✅ Notifications & Announcements
✅ Reports & Dashboard Analytics
✅ OpenAI AI Assistant 🤖
✅ AI Attendance Insights
✅ Employee Self-Service Panel
🛠 Tech Stack: PHP, MySQL, Bootstrap 5, JavaScript, Chart.js, face-api.js, TensorFlow.js & OpenAI API.
📚 Project Details & Features:
Read Full Project Details
🛒 Get Complete Source Code:
Buy Project / Get Source Code
#PHP #MySQL #PHPProject #FinalYearProject #EmployeeManagementSystem #HRMS #AIProject #FaceRecognition #CollegeProject #UpdateGadh
A complete HR & Employee Management System built with PHP and MySQL! 💻
🔥 Key Features:
✅ Employee & Department Management
✅ Face Recognition Attendance
✅ Attendance & Leave Management
✅ Payroll Management
✅ Task Management
✅ Notifications & Announcements
✅ Reports & Dashboard Analytics
✅ OpenAI AI Assistant 🤖
✅ AI Attendance Insights
✅ Employee Self-Service Panel
🛠 Tech Stack: PHP, MySQL, Bootstrap 5, JavaScript, Chart.js, face-api.js, TensorFlow.js & OpenAI API.
📚 Project Details & Features:
Read Full Project Details
🛒 Get Complete Source Code:
Buy Project / Get Source Code
#PHP #MySQL #PHPProject #FinalYearProject #EmployeeManagementSystem #HRMS #AIProject #FaceRecognition #CollegeProject #UpdateGadh