| product | color |
| ------- | ---------- |
| car | red |
| car | green |
| car | blue |
| bike | green |
| bike | white |
| bike | dk blue |
| plane | white |
| plane | pure white |
我想做个 product 和 color 的联动下拉列表，按网上的教程，貌似必须先变为：
| product | color |
| ------- | ---------- |
| car | red |
| bike | green |
| plane | blue |
| | white |
| | dk blue |
| | pure white |
再用 indirect 去联动，有没有可能不转变为这个表，直接用第一个表就能直接做出联动二级下拉列表效果？
