CampusCrate is a student operating system for B.Tech students in India, combining opportunities, academic resources, communities, learning hubs, and career tools in one platform.

Who is CampusCrate built for?

CampusCrate is built for Indian engineering and B.Tech students who need a structured place to discover opportunities, access college resources, join societies, learn technical skills, and build their career profile.

What can students find on CampusCrate?

Students can find hackathons, internships, competitions, notes, test papers, cheatsheets, college communities, DSA and development learning tracks, roadmaps, profiles, and AI career tools.

🗄️SQL

The universal language for talking to databases. Learn it once and analyse data anywhere — Postgres, MySQL, SQLite, BigQuery.

📘Theory & Lessons 💻Code Examples 🔗PostgreSQL Tutorial

4 Phases · 16Topics · Basic → Advanced

Phase 1

SQL Foundations

4 topics

🗄️

Introduction to SQL

Relational model, tables/rows/columns, SQL dialects (Postgres / MySQL / SQLite), how to set up a sandbox in 60 seconds.

🔍

SELECT & Projections

SELECT, column aliases, DISTINCT, expressions, simple functions, comments and SQL formatting.

🎯

WHERE — Filtering Rows

Comparison operators, AND/OR/NOT, BETWEEN, IN, LIKE, IS NULL, three-valued logic and the NULL trap.

📑

ORDER BY, LIMIT & OFFSET

Sort ASC/DESC, multi-column sort, NULLS FIRST/LAST, paginating with LIMIT/OFFSET, dialect differences.

Phase 2

Joins & Aggregation

4 topics

🔗

JOINs

INNER, LEFT, RIGHT, FULL OUTER, CROSS, self-joins, USING vs ON, anti-joins with NOT EXISTS.

🧮

Aggregate Functions

COUNT, SUM, AVG, MIN, MAX, COUNT(DISTINCT), aggregating with NULLs, FILTER (WHERE …).

📊

GROUP BY & HAVING

Grouping rows, the difference between WHERE and HAVING, GROUPING SETS / ROLLUP / CUBE basics.

📦

Subqueries & Set Ops

Scalar / IN / EXISTS subqueries, correlated subqueries, UNION / INTERSECT / EXCEPT.

Phase 3

Schema & Modification

4 topics

🏗️

DDL — CREATE / ALTER / DROP

Tables, columns, data types, ALTER TABLE, schemas, views, dropping with CASCADE.

✏️

DML — INSERT / UPDATE / DELETE

Single & multi-row inserts, UPDATE with joins, safe DELETEs, RETURNING, UPSERT (ON CONFLICT / MERGE).

🔐

Keys & Constraints

PRIMARY KEY, FOREIGN KEY, UNIQUE, NOT NULL, CHECK, ON DELETE CASCADE, normalization 1NF→3NF.

⚡

Indexes & Performance

B-tree vs hash, composite indexes, EXPLAIN / EXPLAIN ANALYZE, when indexes hurt, covering indexes.

Phase 4

Advanced SQL & Practice

4 topics

🪟

Window Functions

OVER (PARTITION BY … ORDER BY …), ROW_NUMBER, RANK, DENSE_RANK, LAG/LEAD, running totals, NTILE.

🌳

CTEs & Recursive Queries

WITH … AS, chaining CTEs, RECURSIVE CTEs for trees / graphs / number generation.

🛡️

Transactions & Isolation

BEGIN / COMMIT / ROLLBACK, ACID, isolation levels, deadlocks, optimistic vs pessimistic locking.

🏆

Practice & Roadmap

LeetCode SQL 50, HackerRank SQL, StrataScratch, build a tiny analytics dashboard, interview classics.