Quizzes de desarrollo web

A primary key column can contain NULL values.
False
True

This query is correct: SELECT * FROM employee WHERE EITHER age = 25 OR age = 30;
False
True

You have to pay to use MySQL.
False
True

You can have several PRIMARY KEY constraints per table.
False
True

We use the DIFFERENT keyword to retrieve different values, for example: SELECT DIFFERENT column_name FROM table_name;
False
True