SQL Mastery
Master database fundamentals, SQL querying, and optimization. 9 phases from basics to advanced interview problems.
Your Progress
Complete all 9 phases to master this track
Master SQL from basics to advanced query optimization. 9 phases covering database design, joins, window functions, indexing, and real interview problems.
Phase 1: SQL Foundations
Master database fundamentals, SQL syntax, and basic querying for Amazon SDE-1 interviews.
What is a Database?
Understand databases, DBMS, RDBMS, and how data is organized.
Tables, Rows, Columns
Understand the relational model: tables, rows, columns, and data types.
Keys and Constraints
Master primary keys, foreign keys, candidate keys, and NOT NULL/UNIQUE/CHECK constraints.
Relationships
Understand one-to-one, one-to-many, and many-to-many relationships.
SELECT and WHERE
Query data with SELECT, filter with WHERE, use comparison and logical operators.
ORDER BY, LIMIT, OFFSET
Sort results, limit output, and paginate with LIMIT and OFFSET.
IN, BETWEEN, LIKE
Use IN, BETWEEN, LIKE, and IS NULL for flexible filtering.
CASE Expressions
Use CASE for conditional logic directly in queries.
Phase 2: SQL Aggregation & Joins
Master aggregation, grouping, and all types of JOINs — the core of SQL interview problems.
COUNT, SUM, AVG, MIN, MAX
Use aggregate functions to summarize data.
GROUP BY and HAVING
Group rows and filter groups with HAVING.
INNER JOIN
Combine rows from multiple tables where the join condition is met.
LEFT and RIGHT JOIN
Keep all rows from one table even when there's no match.
FULL, CROSS, SELF JOIN
Master outer joins, cross joins, and self joins.
Multiple Joins
Chain multiple joins and understand join order and conditions.
Phase 3: SQL Subqueries
Master subqueries including scalar, correlated, EXISTS, and optimization techniques.
Subqueries
Use subqueries in WHERE, FROM, and SELECT clauses.
Correlated Subqueries
Write subqueries that reference outer query columns.
EXISTS and NOT EXISTS
Check for existence of rows using EXISTS.
Phase 4: SQL Advanced Querying
Master UNION, CTEs, and window functions for complex SQL interview problems.
UNION and UNION ALL
Combine results from multiple SELECT statements.
Common Table Expressions
Use WITH clause for readable, modular queries.
Window Functions
Master ROW_NUMBER, RANK, DENSE_RANK, LAG, LEAD, and PARTITION BY.
Window Aggregations
Use SUM() OVER, COUNT() OVER, and running totals with window functions.
Phase 5: SQL Database Design
Master normalization, schema design, and entity-relationship modeling for system design interviews.
Normalization (1NF-BCNF)
Understand normal forms and when to normalize your database.
Denormalization
Know when denormalization improves performance.
Schema Design
Design database schemas for real-world applications and interview questions.
Phase 6: SQL Indexing
Understand how indexes work and when to use them for query optimization.
Phase 7: SQL Transactions
Master ACID properties, transactions, and concurrency control for database interviews.
Phase 8: SQL Performance
Optimize queries, understand execution plans, and solve performance bottlenecks.
Query Optimization
Use EXPLAIN, understand query plans, and optimize slow queries.
N+1 Query Problem
Identify and fix the N+1 query problem in applications.
Pagination Patterns
Master offset pagination and keyset pagination for large datasets.
Phase 9: SQL Interview Problems
Solve real SQL interview problems from beginner to advanced, including Amazon-style questions.
Beginner SQL Problems
Basic SELECT, WHERE, ORDER BY, and simple aggregation problems.
Intermediate SQL Problems
JOINs, subqueries, GROUP BY, HAVING, and window function problems.
Advanced SQL Problems
Complex multi-table queries, window functions, CTEs, and optimization problems.
Amazon-Style SQL Problems
SQL problems modeled after Amazon's data-heavy interview questions.