Custome function error message with Merge

[Mic1979]

Dear all,

I am building this custom function:

(
Input_Table as table,
Adder_Table as table,

Input_Table_Column1 as text,
Input_Table_Column2 as text,
Input_Table_Column3 as text,

Adder_Table_Column1 as text,
Adder_Table_Column2 as text,
Adder_Table_Column3 as text,

Adder as text
) =>

let

Input_Table_Helper_Column = Table.AddColumn (Input_Table, "HelperLPInput", each Text.Combine({
Record.Field(_, Input_Table_Column1),
Record.Field(_, Input_Table_Column2),
Record.Field(_, Input_Table_Column3)}, " "), type text),

Adder_Table_Helper_Column = Table.AddColumn (Adder_Table, "HelperLPAdder", each Text.Combine({
Record.Field(_, Adder_Table_Column1),
Record.Field(_, Adder_Table_Column2),
Record.Field(_, Adder_Table_Column3)}, " "), type text),

// Merge and Expand
Merged_Table = Table.NestedJoin (
Input_Table,
{"HelperLPInput"},
Adder_Table,
{"HelperLPAdder"},
"Adder",
JoinKind.LeftOuter
),

Input_Table_Headers = Table.ColumnNames(Input_Table),
Adder_Table_Headers = Table.ColumnNames(Adder_Table),
List_Header_Difference = List.Difference(Adder_Table_Headers,Input_Table_Headers),

Expanded_Merged_Table = Table.ExpandTableColumn (
Merged_Table,
Adder,
List_Header_Difference,
List_Header_Difference)

in Expanded_Merged_Table

However I am getting this message

An error occurred in the ‘’ query. Expression.Error: The column 'HelperLPInput' of the table wasn't found.
Details:
HelperLPInput

Could you support?

Thanks.

[lbendlin · Accepted solution]

You used the wrong reference.

// Merge and Expand
Merged_Table = Table.NestedJoin (
Input_Table_Helper_Column,
{"HelperLPInput"},
Adder_Table_Helper_Column,
{"HelperLPAdder"},
"Adder",
JoinKind.LeftOuter
),

[lbendlin · Accepted solution]

You used the wrong reference.

// Merge and Expand
Merged_Table = Table.NestedJoin (
Input_Table_Helper_Column,
{"HelperLPInput"},
Adder_Table_Helper_Column,
{"HelperLPAdder"},
"Adder",
JoinKind.LeftOuter
),

[Mic1979 · Accepted solution]

It works, many thanks.