ACCESS SQL Adding Multiple Columns If They Don't Exist - sql

Question

I'm trying to add several new columns to a table that already exists in Access 2007 or 2010 with a query. Right now my code looks like this (yes, I'm terribly new to this):
ALTER TABLE AC_PROPERTY
ADD JAB_1 double,
JAB_2 double,
JAB_3 double;
This correctly adds the three columns when none of them already exist, but if any of them exist I get an error message and the query fails to run. I need it to add each columns only if it does not exist. Can anyone please help with what my code should look like to check if each column exists before trying to add it?
NOTE: I would just do 3 queries for each column, but I actually need to add 20+ columns. This is just a simple example of my actual use.
Thanks a billion!

Answer 1

Here is some old code.... it would be better to just check all fields in the same subroutine rather than opening/closing the DB, TDF, etc.
Option Compare Database
Option Explicit
Function Check_If_Exists()
Dim strStatus As String
' Add calls for the fields you want to append
strStatus = Add_Field("MyFLd2", "Double")
If strStatus = "Exists" Then
Debug.Print "field present"
ElseIf strStatus = "Added" Then
Debug.Print "field added"
End If
End Function
Function Add_Field(strFN, strType) As String
Dim db As DAO.Database
Dim td As DAO.TableDef
Dim fd As DAO.Field
Dim strSQL As String
On Error GoTo Error_Trap
Set db = CurrentDb
Set td = db.TableDefs("Table1")
' ' List all field names
' For Each fd In td.Fields
' Debug.Print fd.Name
' Next fd
If IsNull(td.Fields(strFN)) Then
Add_Field = "Exists"
End If
Set fd = Nothing
Set td = Nothing
Set db = Nothing
Exit Function
Error_Trap:
Debug.Print Err.Number & vbTab & Err.Description
If Err.Number = 3265 Then
Add_Field = "Added"
strSQL = "alter table Table1 ADD " & strFN & " " & strType & ";"
db.Execute strSQL
db.TableDefs.Refresh
End If
Exit Function
Resume
End Function