As you've learned, you can use the following query to get clients' details with ages between 20 and 50:
SELECT * FROM clients WHERE age >= 20 AND age <= 50;
Checking for ranges like this is very common, so in SQL the
BETWEEN keyword provides a useful shorthand for filtering values within a specified range. This query is equivalent to the one above:
SELECT * FROM clients WHERE age BETWEEN 20 AND 50;
It's important to remember that
BETWEEN is inclusive, meaning the beginning and end values are included in the results!