Get value to DT from other DT using Linq

[ppr (Peter Preuss)]

@Hendaryie_Tjoeng

I wanna ask about this line, what is the function of the line Let b?

With the let statement we can memorize for later usage
Here we check if there is right side join pair then use the col2 value otherwise it is set to null
later when constructing the row itemArray we use the prepared value - b

The let keyword

Intro to LINQ - Visual Basic

@Hendaryie_Tjoeng

its means you can use index of DT_Input

Yes we order the LINQ result on the left side datatable rows as mentioned by you about the requirements