VBA Code to Update Cell in Column Based on Value from Drop Down List

Hello,

I need a VBA code to look at each cell in a particular column and update the specific cell content to include a formula.

If the cell in Column A is blank, I need there to be a formula in it that reads {=IFERROR(INDEX(Description_A,MATCH(B3,SKU_A,0)),"")}

However, I also need to be able to have a drop down list in Column A that reads:

Lemon
Cherry
Grapes

So that if I select either of those three, I can type in the corresponding SKU number in SKU List B.

Column B will have a constant formula in it that contains {=IFERROR(INDEX(SKU_B,MATCH(A2,Description_B,0)),"")} which will be overridden if I have the SKU number handy.

Just a background of my dilemma, I have a long list of SKU's and products, but sometimes the people building the pallets are unable to find the product on that list, so they handwrite the description at the end of the list. I want to be able to key in the SKU's that are present on the sheet they turn in in column B, but if they hand write something, I need to be able to select the hand written description in column A so that the formula in Column B will look up and output the respective SKU... sorry if this is overly complicated.

Thanks for the response Ochimus. Unfortunately, I need to be able to select from a dropdown list in column A. I found a post on another site that sort of did it, but it only applied to a dropdown list in one cell, where I need the drop down for the entire column.. I also don't need a "constant data range" like the VBA below indicates. Nevertheless, it would work with some minor tweaking for an entire column, I just don't really know how to do that.

[B][B]Select cell A1 and add your validation list with this source value:

None,Average,Count,Count Numbers,Max,Min,Sum,StdDev,Var,Other Functions...

Add this code to the worksheet code module:

Private Sub Worksheet_Change(ByVal Target As Range)

Const RangeReference = "$B$1:$B$10"

Dim Value As Variant

If Not Intersect(Target, [A1]) Is Nothing Then
Application.EnableEvents = False
Select Case [A1].Value
Case "None"
Value = vbNullString
Case "Average"
Value = "=AVERAGE(^RangeReference)"
Case "Count"
Value = "=COUNT(^RangeReference)"
Case "Count Numbers"
Value = "=SUMPRODUCT(ISNUMBER(^RangeReference)*1)"
Case "Max"
Value = "=MAX(^RangeReference)"
Case "Min"
Value = "=MIN(^RangeReference)"
Case "Sum"
Value = "=AVERAGE(^RangeReference)"
Case "StdDev"
Value = "=STDEV.P(^RangeReference)"
Case "Var"
Value = "=VAR(^RangeReference)"
Case "Other Functions...":
Application.Dialogs(xlDialogFunctionWizard).Show
End Select
If VarType(Value) = vbString Then
[A1].Formula = Replace(Value, "^RangeReference", RangeReference)
ElseIf Not IsEmpty(Value) Then
[A1].Value = Value
End If
Application.EnableEvents = True
End If

End Sub