Copy only records that do not exist in the target table - arrays

Question

Having two tables (the source and target) intend to copy only the records from the source table that do not exist in the target table (making the comparison with the value of a specific cell in each record). I thought to do it using arrays, but as I am new in this area, needed help.
Examples:
Source Table
ID Date Description
115 01-Ago Description1
120 05-Ago Description2
130 03-Ago Description5
110 08-Ago Description4
105 06-Ago Description6
Destination Table
ID Date Description
130 03-Ago Description5
110 08-Ago Description4
I want to add in the target table records from the source table that do not exist in the target table (ID's 115,120,105 in this example). Thank you!
I'm almost there. After consulting some other questions, I need something like this:
Sub Tests()
Dim MyArray() As String
Dim tgtLastRow, srcLastRow As Integer
Dim rngTarget, rngSource, cel As Range
Dim Delim As String
Delim = "#"
tgtLastRow = Range("H1").End(xlDown).Row
srcLastRow = Range("A1").End(xlDown).Row
Set rngTarget = Range("H2:H" & tgtLastRow)
Set rngSource = Range("A2:A" & srcLastRow)
MyArray = rngTarget.Value
strg = Join(MyArray, Delim)
strg = Delim & strg
For Each cel In rngSource
If InStr(1, strg, Delim & cel.Value & Delim, vbTextCompare) Then
Else
'Copy the row or range here
End If
Next cel
End Sub
But now, I have one of two problems:
If I declare MyArray as string type I have problems loading values to array
If I declare MyArray as variant type I have problems in the Join
Can anyone help-me please??

Answer 1

All you need is to use Either Collection object, or Dictionary Object. These objects help a lot when you try to find the unique records.
Let us take an example, We have two sheets: Source and Target.
You need to loop through Column A in both sheets and move the data from Source Worksheet to target Worksheet. Following is the code, not tested, but it should do the trick. I have added comments so you can easily understand and fit this in your situation easily
Dim ids As Collection
Sub MoveData()
On Error GoTo MoveData_Error
Set ids = New Collection
Dim sourceRange As Range
Dim idRange As Range
Dim cell As Range
Set sourceRange = Range("A1:A100") 'assign your source range here. Code will try to pick ID in this range, and check in ID Range
Set idRange = Range("A1:A100") ' assign your target range here. Code will find the ID in this range
'load all ids from target range in the collection.
On Error Resume Next ' suppressing the error if any duplicate value is found
For Each cell In idRange.Cells
ids.Add cell.Value, cell.Value ' adding in collection to maintain a unique collection
Err.Clear
Next cell
On Error GoTo MoveData_Error
'now I have information about all the availabe IDs in id collection. Now I will loop through to check
For Each cell In sourceRange
If ShouldCopy(cell) Then
'write your code to copy
End If
Next cell
On Error GoTo 0
Exit Sub
MoveData_Error:
MsgBox "Error " & Err.Number & " (" & Err.Description & ") in procedure MoveData of VBA Document Sheet1"
End Sub
Public Function ShouldCopy(cell As Range) As Boolean
On Error GoTo ShouldCopy_Error
If cell.Value = "" Or IsEmpty(cell.Value) Then Exit Function
ids.Add cell.Value, cell.Value ' if error occurs here, then it means the id has been already moved or found in the ID worksheet range
ShouldCopy = True
On Error GoTo 0
Exit Function
ShouldCopy_Error:
ShouldCopy = False
End Function
If you face any issues in understanding and need any help, please let me know.
Thanks,
V

Answer 2

Add a lookup to your source data flagging each record as either present or absent and then bounce your macro off of that column (i.e only move it into target if the lookup = absent).