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What does NMET represent in numeric data types?
A special value that represents either unknown or inapplicable data, not the same as zero.
What happens when a WHERE clause evaluates to null for values in a row?
The row is not selected.
What is the purpose of a NOT NULL constraint?
It prevents a column from having a NULL value.
What does the SQL statement IS NULL return?
TRUE when the value is NULL.
What does the SQL statement IS NOT NULL return?
TRUE when the value is not NULL.
In NULL logic, what is the result of TRUE AND NULL?
NULL.
In NULL logic, what is the result of NULL OR FALSE?
NULL.
What is the result of NOT NULL in NULL logic?
NULL.
What is the significance of a WHERE clause that selects NULL values?
It never returns any rows because the WHERE clause is always null.
