Understand SQL portability: ANSI SQL standard (core works everywhere) vs database-specific extensions (vendor lock-in)

Master common compatibility issues: LIMIT vs TOP vs FETCH, string concatenation (|| vs + vs CONCAT), date functions, auto-increment syntax

Learn abstraction strategies: ORMs (Hibernate, SQLAlchemy), query builders (jOOQ, Knex.js), database abstraction layers (JDBC, PDO)

Understand migration challenges: data type mapping (VARCHAR vs TEXT), index syntax differences, stored procedure incompatibility

Master feature detection: Check database version/features at runtime, conditional SQL generation, graceful degradation

Learn real-world patterns: GitLab (PostgreSQL + MySQL support), WordPress (MySQL + MariaDB), Metabase (10+ database support)

Understand SQL portability: ANSI SQL standard (core works everywhere) vs database-specific extensions (vendor lock-in)

Master common compatibility issues: LIMIT vs TOP vs FETCH, string concatenation (|| vs + vs CONCAT), date functions, auto-increment syntax

Learn abstraction strategies: ORMs (Hibernate, SQLAlchemy), query builders (jOOQ, Knex.js), database abstraction layers (JDBC, PDO)

Understand migration challenges: data type mapping (VARCHAR vs TEXT), index syntax differences, stored procedure incompatibility

Master feature detection: Check database version/features at runtime, conditional SQL generation, graceful degradation

Learn real-world patterns: GitLab (PostgreSQL + MySQL support), WordPress (MySQL + MariaDB), Metabase (10+ database support)