Lookup not retrieving the exact phrase for the row

[Amitai_Hirshman]

Hi
I have an ‘orders’ table with SKU column, and an ‘inventory’ table with a matching SKU column and a weight column. I built a virtual column in the ‘orders’ table and trying to retireve the correct weight for each order using the lookup expression, in excel I would use vlookup.
it is retriveing the first wieght in the table for all the rows and not the correct answer for each SKU
What am I doing wrong?
this is my formula:
lookup([sku],inventory,sku,weight)