SQL and databases
6 questions
How to optimize queries?
•EXPLAIN.
•Indexes.
•Avoid SELECT *.
•LIMIT.
•No functions on indexes.
PostgreSQL vs MySQL?
•PG: complex queries.
•MySQL: simple CRUD.
•PG is stricter.
•MySQL reads faster.
•Both production-ready.
SQL and databases: how to design schema and normalize tables?
Regarding «SQL and databases», start with reproducibility: minimal example, version, steps. This is half of debugging.
SQL and Databases: How to choose indexes and read EXPLAIN plans?
Practice for "SQL and Databases": write a test/check that breaks, then fix the code. This way you don't "treat symptoms".
SQL and Databases: How to perform migrations and version the schema?
Answer on "SQL and Databases": read the documentation and errors thoroughly. An error message almost always indicates what is wrong.
SQL and Databases: How to set up backups and recovery?
For "SQL and Databases" it is useful: logging, profiling, and working with metrics. Optimization without measurements is guesswork.