how to config SKU?

Take T-Shirt for example, T-Shirt has product name, color, size and stock quantity.

I want such a result: One T-Shirt has different SKU

SKU1: productname + White color + M size + 200 quantity
SKU2: productname + White color + L size + 100 quantity
SKU3: productname + Black color + M size + 50  quantity
SKU4: productname + Black color + L size + 50  quantity

How to realize it?

To do this you create multiple product variants (SKUs)

In administration select your Product, click on the "Product Variants (SKU)" tab and click "Add a new product variant"

You can then set individual names for each variant, manage stock levels etc.

Hope this helps,

Ben

Or you can extend attribute functionality to support SKU prefix/postfix (needs developer skills)