The most widely known query optimisation rule is that developers should always avoid SELECT *. Even when all columns are needed, they should list their names, because more columns could be created in the future. But developers find this really Continue reading How slow is SELECT * ?
Reducing the number of queries is important with any DBMS. There are two reasons for this: reducing the latency of applications; and reducing the workload for the database servers. Continue reading MariaDB/MySQL: use SQL properly to run less queries
SQL columns can be NULL or NOT NULL. Let’s see what are the good and bad reasons to declare NULL columns. Continue reading When to use NULLable columns in relational databases
Updating triggers in production without causing a service disruption Continue reading Updating triggers in production with MariaDB and MySQL
Does NULL mean “no value”? Or does it mean “an unknown value”? Its semantics and history are ambiguous and inconsistent. Continue reading What does NULL mean in SQL?