INNER, LEFT, RIGHT, FULL joins.

Overview

INNER, LEFT, RIGHT, FULL joins.

Example 

  SELECT * FROM users WHERE active = true;

Common Use Cases

  • Data retrieval
  • Report generation
  • Application queries

Pitfalls to Avoid

  • SELECT * in production
  • Missing indexes on WHERE columns
  • JDBC
  • JPA
  • MyBatis

Best Practices

  • Understand when to use sql joins versus simpler alternatives
  • Write unit tests covering edge cases and failure paths
  • Follow Java conventions and prefer standard library APIs when available
  • Profile before optimizing — measure impact in your specific workload