SKU Stock Keeping Unit, is a unique identification code, usually alphanumeric.
It allows a particular product to be tracked for inventory purposes. Typically, an SKU (pronounced with the individual letters or as SKYEW) is associated with any purchasable item in a store or catalog.
You can choose any format you like for SKU but usually there is some system for choosing numbers, for example, a woman’s blouse of a particular style and size might have an SKU of “3726-8,” meaning “Style 3726, size 8.”
SKU is unique identification code.You can not create a product a with already existed SKU its not possible.
You should be able upon saving the MS Excel doc to use , instead of ; without any repercussions. I believe you can also provide an escape sequence or text delimiter such as " to allow for either , or ; in context without it being treated as a delimiter.