Combine 2 fields into 1 field.

Combine 2 fields into 1 field.

I need to combine 2 fields, one of which is an auto number field and the other is a single line text field. I tried using the following syntax in the workflow:

input.SKUID = toString(input.SKU) + " - " + toString(input.Order_Type);

but my output is as below:


Please help.