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See the whole table
Select some columns
Filtering rows
Logic
Text patterns
To be or NULL to be
20. Comparisons with NULL
A little bit of mathematics
Let's practice

## Instruction

Good job. Remember, NULL is a special value. It means that some piece of information is missing or unknown.

If you set a condition on a particular column, say AGE < 70, the rows where age is NULL will always be excluded from the results. Let's check that in practice.

In no way does NULL equal zero. What's more, the expression NULL = NULL is never true in SQL!

## Exercise

Select all columns for cars whose price column is greater than or equal to zero.

Note that the Opel with an unknown price is not in the result.

### Stuck? Here's a hint!

Type:

SELECT *
FROM car
WHERE price >= 0;