Using insert into where not exists in VBA - sql

Question

I have a lovely form and a lovely table in MS access (I promise). I would like to insert into this table at the press of a button using where not exists but I am getting a not-so-friendly run-time error 3067: "Query input must contain at least one table or query."
My query already does...
strSQL = "insert into tbl_MAP_systemTask (TaskID, SystemID) " & _
" Values (" & taskID & ", " & sysID & _
") where not exists " & _
" (select M.TaskID, M.SystemID from tbl_MAP_systemTask as M where M.TaskID = " & taskID & _
" and M.SystemID = " & sysID & ");"
Debug.Print strSQL
DoCmd.RunSQL (strSQL)
strSQL is now
insert into tbl_MAP_systemTask (TaskID, SystemID)
Values (1, 1)
where not exists
(select M.TaskID, M.SystemID
from tbl_MAP_systemTask as M where M.TaskID = 1 and M.SystemID = 1);
Can anyone shed any light on
a) what I broke?
b) how to fix it?

Answer 1

Well instead of using a SubQuery, you could use a Domain function to get this going,
If Dcount("*", "tbl_MAP_systemTask", "TaskID = " & taskID & " AND SystemID = " &sysID) = 0 Then
strSQL = "INSERT INTO tbl_MAP_systemTask (TaskID, SystemID) " & _
" VALUES (" & taskID & ", " & sysID & ")
CurrentDb.Execute strSQL
Else
MsgBox "The Data already exists in the table, so nothing was added."
End If

Answer 2

Try this:
strSQL = "insert tbl_MAP_systemTask (TaskID, SystemID) " & _
" select " & taskID & ", " & sysID & _
" where not exists " & _
" (select M.TaskID, M.SystemID from tbl_MAP_systemTask as M where M.TaskID = " & taskID & _
" and M.SystemID = " & sysID & ");"
=>
insert tbl_MAP_systemTask (TaskID, SystemID)
select 1, 1
where not exists
(select M.TaskID, M.SystemID
from tbl_MAP_systemTask as M where M.TaskID = 1 and M.SystemID = 1);
and seems to work in my case. Seems like the where not exists needs a select statement, so you have to model your insert like this.

Answer 3

Maybe you can use a recordset to insert these values.
Dim rs as Recordset
Set rs = Currentdb.openRecordset("SELECT * FROM tbl_MAP_systemTask WHERE TaskID=" & Me.TaskID & " AND SystemID=" & Me.SystemID)
if not (rs.eof or rs.bof) then
rs.addnew
rs.TaskID = Me.TaskID
rs.SystemID = Me.SystemID
rs.update
end if
rs.close
set rs = nothing

Answer 4

TOP 1 clause is must in the main query.
INSERT INTO tbl_MAP_systemTask (TaskID, SystemID)
SELECT TOP 1 1 AS TaskID 1 AS SystemID
FROM tbl_MAP_systemTask
WHERE NOT EXISTS (SELECT TOP 1 TaskID,SystemID FROM
tbl_MAP_systemTask WHERE TaskID = 1 and SystemID=1);
If tbl_MAP_systemTask table is empty or if there is only one record in the table then TOP 1 clause must be omitted in sub-query.
I have included Top 1 clause is sub-query for performance purpose.