5 docs tagged with "sql"

Consolidated interview Q&A for the Databases domain — SQL, indexes, transactions, connection pooling, NoSQL, and schema migration — beginner through advanced.

How database indexes work, when to add them, how to read EXPLAIN plans, and common indexing pitfalls that hurt performance.

Hands-on examples covering index creation, composite indexes, covering indexes, and reading EXPLAIN plans in PostgreSQL.

Core SQL syntax and concepts — SELECT, JOIN types, GROUP BY, window functions, and subqueries — with Spring Boot JDBC context.

Hands-on SQL examples covering JOINs, GROUP BY, window functions, and subqueries in a Spring Boot JDBC context.