Given that WKND_DATE can also be null, get the field as a Nullable(Of DateTime)
(DateTime?
) like so:
Dim query = From c In dtDollars.AsEnumerable() _
Join r In dtUnits.AsEnumerable() _
On c.Field(Of String)("UPC") Equals r.Field(Of String)("UPC") _
Select _
New _
With {.UPC = r.Field(Of String)("UPC"), .WIC_NUMBER = c.Field(Of String)("WIC_NUMBER"), _
.WAG_ITEM_DESC = c.Field(Of String)("WAG_ITEM_DESC"), _
.WAG_BRAND = c.Field(Of String)("WAG_BRAND"), .UOM = c.Field(Of String)("UOM"), _
.GSK_PROMO_GRP = c.Field(Of String)("GSK_PROMO_GRP"), _
.TOTAL_DOLLARS = c.Field(Of Decimal?)("TOTAL_DOLLARS"), _
.TOTAL_UNITS = r.Field(Of Integer?)("TOTAL_UNITS"), _
.WKND_DATE = c.Field(Of DateTime?)("WKND_DATE")}