Your roadmap to real skills.

Relational Database Basics

Explain tables, rows, columns, primary keys, foreign keys; set up Postgres or Neon.

Basic SQL: SELECT, INSERT, UPDATE, DELETE

Use SELECT/FROM/WHERE/ORDER BY/LIMIT and the basic mutation operations.

Filtering and Sorting

Filter with AND/OR/NOT, LIKE, IN, BETWEEN, IS NULL; use DISTINCT.

JOINs

Use INNER / LEFT / RIGHT / FULL OUTER JOINs and reason about them visually.

GROUP BY and Aggregations

Use GROUP BY + HAVING + aggregations to summarize data into reports.

Subqueries and CTEs

Use subqueries, EXISTS, CTEs, and recursive CTEs to express complex queries readably.

Window Functions

Use window functions: ROW_NUMBER, RANK, DENSE_RANK, LAG, LEAD, running totals.

Indexes and Query Performance

Reason about B-tree indexes, composite index direction, and use EXPLAIN ANALYZE.

Transactions and ACID

Use BEGIN/COMMIT/ROLLBACK, understand ACID, pick the right isolation level.

Database Design and Normalization

Apply 1NF/2NF/3NF, decide when to denormalize, draw ER diagrams, pick data types.

PostgreSQL-Specific Features

Use Postgres-specific features: JSONB, arrays, full-text search, pg_trgm, EXPLAIN ANALYZE in depth.

SQL from Applications

Use SQL from Node.js, Python, and Prisma with parameterized queries (no SQL injection).

Database Performance

Read EXPLAIN ANALYZE, fix N+1 queries, size connection pools, and run zero-downtime migrations with the expand/contract pattern.

Passion Project: Schema + Query Gallery

Design + ship a realistic Postgres schema (8+ tables, ER diagram, indexes) with a 15-query gallery, hosted on Neon.

SQL Job Readiness

Translate SQL skills into resume bullets + interview answers for backend / data eng / analyst roles.