Comparisons are tricky when NULL values are involved. But some databases offer some special, handy syntax to solve the problem. Continua a leggere NULL comparisons in MariaDB, PostgreSQL, and SQLite
It is quite common to use an equality condition and an IS NULL condition on the same columns. Unfortunately, this could make queries very slow. Continua a leggere MariaDB/MySQL IS NULL conditions and indexes
SQL columns can be NULL or NOT NULL. Let’s see what are the good and bad reasons to declare NULL columns. Continua a leggere When to use NULLable columns in relational databases
Does NULL mean “no value”? Or does it mean “an unknown value”? Its semantics and history are ambiguous and inconsistent. Continua a leggere What does NULL mean in SQL?