FIX: Acc2000: "Not a Valid Alias" Jet 3068 Error Message

When you run a SQL query containing more than 22 UNION statements using Microsoft Jet 4.0 the following error appears: The same query worked without error when using Microsoft Jet 3.x.

This problem is caused by a bug in the underlying Microsoft Jet 4.0 database engine that is included with the Microsoft Data Access Components (MDAC) versions noted in the earlier. As a result of this bug Microsoft Jet 4.0 is unable to execute queries containing more than 22 UNION statements.

To resolve this problem, download and install the latest Jet 4.0 service pack. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.

Note The Microsoft Jet Engine does not ship with MDAC 2.6.

This problem was corrected in Jet 4.0 SP 5.

Steps to Reproduce the Behavior

1. Install MDAC 2.1 SP2 on a test computer.
2. Create an ODBC DSN to the NorthWind.mdb sample database called NorthWind.
3. Run the following VBA code. NOTE: The VBA project requires a reference to the "Microsoft ActiveX Data Objects 2.1 Library.":

   Sub TestUNIONError()
   Dim conn As New ADODB.Connection
   Dim sql As String
   Dim i As Long
   
       conn.Open "NorthWind"
       For i = 1 To 22
           sql = sql & "select * from shippers UNION "
       Next i
       sql = sql & "select * from shippers"
       conn.Execute sql
       conn.Close
   
   End Sub
   					

4. Run the application. It results in the following error message:
   Run-time error '-2147467259 (80004005)'.
   [Microsoft][ODBC Microsoft Access Driver] Not a valid alias name.