Update excel cells based on condition

How do we update certain cells in excel based on condition.
I have an excel in which I need to check in a column where its false I need to update a relevant cell taken from another excel
Query Im trying

(From row1 In Sheet1.AsEnumerable()
Where Not row1.Field(Of Boolean)(“diff”)
Join row2 In Sheet2.AsEnumerable() On row1.Field(Of Integer)(“Id”) Equals row2.Field(Of Integer)(“code”)
Select row1.SetField(“dt1col”, row2(“dt2 col”)))

But its showing row2 is not declared error.

sample table :

table 1

ID Date1 Date2 Diff …
1 24/10 26/3 False …

Table 2
Code Date
1 24/10

Result in table 1
ID Date1 Date2 Diff
1 24/10 24/10 True …


Why dont you join the tables using join activity?