Compare Two Different Spreadsheets with Similar Information

Hello,

I'm trying to compare two spreadsheets;

one is from my internal system that will list an items sku number and current inventory count for that item in separate columns

the other is from my website which also lists an items sku number and current count of that item on the website, also in separate columns

the end result I'm wanting would hopefully look like this

the difference column would show me where I may have mistakes;

• sku# 1006WG3 this shows me I have 1 to many on my website
• sku# 107G1 blank in the difference column because this item is not on my website (this being blank is important, because I have much more inventory in my internal system than I do on my website and I want the same sku to appear next to each other in the same rows)
• the remaining sku #'s would all be correct in telling me I either need to list another on my website or all current inventory is listed

My main question would be organizing the two different sets of sku numbers and their corresponding inventory count, so the same sku from the internal system and from the website are in the same row.

Calculating the difference between the two inventory counts I'm assuming is a simple formula after they are organized.

Sorry for the long winded question, hopefully this is enough information to get an answer.