Virtual columns not populating

[StephenSaid]

I have a table with one field and some virtual columns.

For some reason, the virtual columns are not populating.

This is one of the expressions:

LOOKUP("Item_Code", "StockList", "Item_Code", "Supplier_Name")

This is the source table - StockList

I can't figure out what is happening.

[StephenSaid]

I had an error in my expression.

Should read:

LOOKUP([Item_Code], "StockList", "Item_Code", "Supplier_Name")