MariaDB [supply]> SELECT DISTINCT p.pnum, p.pname
    -> FROM part AS p INNER JOIN supply AS s1 ON (p.pnum = s1.PNUM)
    -> WHERE s1.SNUM = 'S2'
    -> AND NOT EXISTS -- subquery (Is an empty set?)
    -> (SELECT s2.*
    ->  FROM supply AS s2
    ->  WHERE s2.PNUM = p.pnum
    ->  AND s2.SNUM = 'S3');
+------+--------+
| pnum | pname  |
+------+--------+
| P1   | Drum   |
| P2   | Hammer |
+------+--------+
2 rows in set (0.001 sec)

MariaDB [supply]> SELECT DISTINCT p.pnum, p.pname
    -> FROM part AS p INNER JOIN supply AS s1 ON (p.pnum = s1.PNUM)
    -> INNER JOIN supply AS s2 ON (p.pnum = s2.PNUM)
    -> WHERE s1.SNUM = 'S2'
    -> AND s2.SNUM = 'S3';
+------+----------+
| pnum | pname    |
+------+----------+
| P4   | Micropod |
+------+----------+
1 row in set (0.000 sec)

MariaDB [supply]> SELECT DISTINCT p.*
    -> FROM part AS p INNER JOIN supply as s ON (p.pnum = s.snum)
    -> WHERE s.snum = 'S2' or s.snum = 'S3'
    -> ORDEY BY p.weight DESC;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'ORDEY BY p.weight DESC' at line 4
MariaDB [supply]> 
MariaDB [supply]> SELECT DISTINCT p.*
    -> FROM part AS p INNER JOIN supply as s ON (p.pnum = s.snum)
    -> WHERE s.snum = 'S2' or s.snum = 'S3'
    -> ORDER BY p.weight DESC;
Empty set (0.001 sec)

MariaDB [supply]> SELECT DISTINCT p.*
    -> FROM part AS p INNER JOIN supply as s ON (p.pnum = s.pnum)
    -> WHERE s.snum = 'S2' or s.snum = 'S3'
    -> ORDER BY p.weight DESC;
+------+-------------+-------+--------+
| PNUM | PNAME       | COLOR | WEIGHT |
+------+-------------+-------+--------+
| P2   | Hammer      | Green |     20 |
| P6   | Musical Box | Blue  |     13 |
| P1   | Drum        | Green |     10 |
| P7   | Bear        | Blue  |      9 |
| P4   | Micropod    | Red   |      4 |
| P5   | Blue Spur   | Blue  |      3 |
+------+-------------+-------+--------+
6 rows in set (0.001 sec)

MariaDB [supply]> SELECT DISTINCT p.*
    -> FROM part AS p INNER JOIN supply as s ON (p.pnum = s.pnum)
    -> WHERE s.snum = 'S2' or s.snum = 'S3'
    -> ORDER BY p.weight DESC
    -> LIMIT 4;
+------+-------------+-------+--------+
| PNUM | PNAME       | COLOR | WEIGHT |
+------+-------------+-------+--------+
| P2   | Hammer      | Green |     20 |
| P6   | Musical Box | Blue  |     13 |
| P1   | Drum        | Green |     10 |
| P7   | Bear        | Blue  |      9 |
+------+-------------+-------+--------+
4 rows in set (0.002 sec)

MariaDB [supply]> SELECT DISTINCT p.*
    -> FROM part AS p INNER JOIN supply as s ON (p.pnum = s.pnum)
    -> WHERE s.snum = 'S2' or s.snum = 'S3'
    -> ORDER BY p.weight DESC
    -> LIMIT 2,3;
+------+----------+-------+--------+
| PNUM | PNAME    | COLOR | WEIGHT |
+------+----------+-------+--------+
| P1   | Drum     | Green |     10 |
| P7   | Bear     | Blue  |      9 |
| P4   | Micropod | Red   |      4 |
+------+----------+-------+--------+
3 rows in set (0.001 sec)

MariaDB [supply]> exit;