This is my parts Table
这是我的零件表
---------+---------+----------------+--------------+
| part_id | part_no | purchase_price | retail_price |
+---------+---------+----------------+--------------+
| 1 | 11 | 600 | 650 |
| 2 | 12 | 200 | 260 |
| 3 | 13 | 200 | 280 |
| 4 | 14 | 520 | 600 |
| 5 | 15 | 150 | 180 |
| 6 | 16 | 160 | 185 |
| 7 | 17 | 180 | 200 |
| 8 | 18 | 600 | 710 |
| 9 | 19 | 500 | 580 |
| 10 | 20 | 780 | 850 |
| 11 | 21 | 145 | 200 |
| 12 | 22 | 6200 | 6500 |
| 13 | 23 | 1030 | 1100 |
| 14 | 24 | 720 | 800 |
| 15 | 25 | 400 | 600 |
| 16 | 26 | 1400 | 1600 |
| 17 | 27 | 800 | 1000 |
| 18 | 28 | 90 | 100 |
| 19 | 29 | 1500 | 1600 |
| 20 | 30 | 2000 | 2100 |
+---------+---------+----------------+--------------+
---------+-
