Quizzes de desarrollo web

There are different versions of the SQL language.
False
True

This query is correct: SELECT column1 FROM table1 UNION SELECT column2 FROM table2;
False
True

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

SQL can retrieve data from a database.
False
True

UNIQUE and NOT NULL are contraints.
False
True