You know how to query data. Now learn to control it. You can write JOINs. You understand GROUP BY. Window functions no longer terrify you. But there's a gap between writing queries and truly mastering databases—between asking for data and architecting systems that scale. SQL Mastery bridges that gap. In 34 focused days, you'll transform from someone who queries databases into someone who builds, optimizes, and commands them. What You'll Master: Part 5: Database Design (Days 57-70) Stop querying other people's databases—start building your own. Learn data modeling fundamentals that separate amateur schemas from professional architecture. Master primary keys for unique identification and foreign keys for bulletproof relationships. Explore PostgreSQL's rich data types and choose wisely for every column. Write CREATE TABLE statements with confidence. Implement constraints that protect your data: NOT NULL, DEFAULT, CHECK, and UNIQUE. Understand normalization—eliminating redundancy the right way—and denormalization—knowing when to break the rules for performance. Modify existing structures with ALTER TABLE and handle destructive operations safely with DROP and TRUNCATE. Your Week 10 project: design a complete library management system from scratch. Part 6: Data Manipulation (Days 71-77) Reading data is only half the story. Now you'll write it. Master bulk INSERT operations and the COPY command for lightning-fast data loading. Learn UPSERT patterns with ON CONFLICT—insert if new, update if exists—the pattern every production system needs. Dive deep into transactions: BEGIN, COMMIT, ROLLBACK, and SAVEPOINTS for partial rollbacks. Understand ACID properties—Atomicity, Consistency, Isolation, Durability—the guarantees that keep your data safe. Use the RETURNING clause to get data back from modifications. Import and export data between systems like a pro. Your Week 11 project: build a complete e-commerce data pipeline with transactional integrity. Part 7: Indexes & Performance (Days 78-84) Fast queries don't happen by accident. They're engineered. Understand B-tree indexes—the workhorse of database performance—and when to use Hash, GIN, and GiST indexes for specialized cases. Create partial indexes that only index what matters and expression indexes for computed values. Master EXPLAIN ANALYZE—your X-ray vision into query execution. Read query plans like a database expert: sequential scans, index scans, bitmap scans, nested loops, hash joins, and merge joins. Learn systematic query tuning: identify bottlenecks, apply fixes, measure improvements. Understand database maintenance with VACUUM and ANALYZE. Manage connections and resources for production workloads. Your Week 12 project: perform a complete performance audit on a slow database and make it fast. Part 8: Advanced PostgreSQL (Days 85-90) The power features that complete your arsenal. Build views for abstraction—virtual tables that simplify complex queries. Create materialized views for performance—cached results that make dashboards instant. Write stored procedures for reusable server-side logic and custom functions for calculations that belong in the database. Implement triggers for automatic actions—audit logging, timestamp updates, derived data maintenance—that fire without application code. Your final project on Day 90: put it all together in a comprehensive e-commerce system with schemas, triggers, views, functions, and optimized indexes.