\!h Example - Engineers who've been working longer than the least experienced producer:
SELECT engineer_name, years -- return engineer_name and year...
FROM engineer WHERE years > ANY -- ...where engineer.years is greater than any value of producer.years
(SELECT years FROM producer);
+---------------+-------+
| engineer_name | years |
+---------------+-------+
| George Martin |    40 | -- e.g. 40 is greater than atleast one value in producer.years
| Eddie Kramer  |    38 |
| Jeff Jarratt  |    40 |
| Ed Stasium    |    25 |
+---------------+-------+

\!h Example 2 - producers that are also engineers
SELECT producer_name FROM producer WHERE
producer_name = ANY
(SELECT engineer_name FROM engineer);

\!h Using IN (same result as above):
SELECT producer_name FROM producer WHERE producer_name
IN (SELECT engineer_name FROM engineer);

\!h Using NOT IN - engineers that aren't producers
SELECT engineer_name FROM engineer WHERE
engineer_name NOT IN
(SELECT producer_name FROM producer);