Can't union two tables even though ADODB confirms equal field counts - vba

Question

I'm not able to union two csvs even though ADODB confirms via .Fields.Count that they both have the same number of columns.
Here's the query that's failing:
select * from csv1.csv union select * from csv2.csv
with the error message:
The number of columns in the two selected tables or queries of a union query do not match
However, when I do select * from csv1.csv and select * from csv2.csv separately, ADODB confirms that .Fields.Count = 8 for both.
Possible key to the problem:
Do I need to create two separate connections? I'm only creating one connection (to the first csv) even though there are two csvs in the query.
I was trying to figure out how to do two separate connections for the same query and it seemed like people weren't finding that necessary - I couldn't find two connections mentioned in equivalent queries people were running against csvs.
Per #Parfait's request to see more of the code:
GetDataFromCSV
Public Function GetDataFromCSV(ByVal fileReport As Scripting.File, ByVal strQuery As String, ByVal arrSourceReports As Variant) As Boolean
Dim strRevisedQuery As String
strRevisedQuery = GetRevisedQueryWithFileAliasesReplacedWithTrueFileNames(strQuery, arrSourceReports)
Dim cnn As ADODB.Connection
Set cnn = OpenConnectionToCSV(fileReport)
If cnn Is Nothing Then
GetDataFromCSV = False
Exit Function
End If
GetDataFromCSV = QueryDataFromCSV(cnn, strRevisedQuery, fileReport.Name, fileReport.Name)
End Function
OpenConnectionToCSV
Private Function OpenConnectionToCSV(ByVal fileCSV As Scripting.File, Optional boolHeadersPresent As Boolean = True) As ADODB.Connection
Dim cnn As ADODB.Connection
Set cnn = New ADODB.Connection
cnn.ConnectionTimeout = 0
Dim strfileCSVParentFolderPath As String
strfileCSVParentFolderPath = fileCSV.ParentFolder
If Right(strfileCSVParentFolderPath, 1) <> Application.PathSeparator Then strfileCSVParentFolderPath = strfileCSVParentFolderPath & Application.PathSeparator
Dim strConn As String
If boolHeadersPresent = False Then
strConn = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" & strfileCSVParentFolderPath & ";Extended Properties=""text;HDR=NO;FMT=Delimited"""
Else
strConn = "Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" & strfileCSVParentFolderPath & ";Extended Properties=""text;HDR=YES;FMT=Delimited"""
End If
If strConn <> vbNullString Then
On Error GoTo ErrorHandler
Dim lngRetryCount As Long
lngRetryCount = 0
cnn.Open strConn
On Error GoTo 0
Set OpenConnectionToCSV = cnn
End If
Exit Function
ErrorHandler:
Select Case True
Case InStr(1, Err.Description, "Connect timeout occurred", vbTextCompare) > 0
If lngRetryCount < 30 Then
Application.Wait DateAdd("s", 1, Now)
lngRetryCount = lngRetryCount + 1
Resume
Else
MsgBox "Can't connect to " & fileCSV.Path & ". Reading this file will be skipped."
Exit Function
End If
Case Else
MsgBox "Getting data from " & fileCSV.Name & " has failed with the following error message: " & Err.Number & ": " & Err.Description
On Error GoTo 0
Resume
End Select
End Function
QueryDataFromCSV
Private Function QueryDataFromCSV(ByVal cnn As ADODB.Connection, ByVal strQuery As String, ByVal strCSVName As String, ByVal strFinalReportTitle As String) As Boolean
QueryDataFromCSV = True
Dim cmd As ADODB.Command
Set cmd = PrepareQueryCommand(cnn, strQuery)
CreateQueryDebugLog cmd.CommandText
Dim rst As ADODB.Recordset
Set rst = New ADODB.Recordset
rst.Open cmd
Dim Loop1 As Long
With rst
For Loop1 = 1 To .Fields.Count
If .Fields(Loop1 - 1).Name = "F" & Loop1 Then
If Loop1 < 4 Then
MsgBox "Can't retrieve data from " & strCSVName & " because it is formatted improperly."
Else
MsgBox "Can't retrieve data from " & strCSVName & " because it is delimited improperly. The file is most likely delimited with a comma even though it has addresses or other fields that contain commas. Ask Encounters IT to change this report's delimiter to another character, such as | (pipe), in the Tidal batch file."
End If
QueryDataFromCSV = False
Exit Function
End If
Next Loop1
End With
CopyThisCSVRecordsetToResultSheets rst, strFinalReportTitle
cnn.Close
Set rst = Nothing
Set cmd = Nothing
Set cnn = Nothing
End Function
The error is occurring at rst.Open cmd in the above function QueryDataFromCSV
Illustrating schema.ini creation for #Comintern:
GetRevisedQueryWithFileAliasesReplacedWithTrueFileNames
Private Function GetRevisedQueryWithFileAliasesReplacedWithTrueFileNames(ByVal strQuery As String, ByVal arrSourceReports As Variant) As String
Dim FSO As Scripting.FileSystemObject
Set FSO = New Scripting.FileSystemObject
Dim lngPosition As Long
lngPosition = 0
Do Until lngPosition > Len(strQuery)
Dim lngStartPosition As Long
lngStartPosition = InStr(lngPosition + 1, strQuery, "from", vbTextCompare) + 5
If lngStartPosition > lngPosition Then
Dim lngEndPosition As Long
lngEndPosition = InStr(lngStartPosition + 1, strQuery, " ", vbTextCompare)
If lngEndPosition = 0 Then lngEndPosition = Len(strQuery) + 1
Dim strSourceReportTitle As String
strSourceReportTitle = Mid(strQuery, lngStartPosition, lngEndPosition - lngStartPosition)
Dim Loop2 As Long
For Loop2 = LBound(arrSourceReports, 1) To UBound(arrSourceReports, 1)
If arrSourceReports(Loop2, 1) = strSourceReportTitle Then Exit For
Next Loop2
Dim fileSource As Scripting.File
Set fileSource = FSO.GetFile(arrSourceReports(Loop2, 3))
If arrSourceReports(Loop2, 2) = "TAB" Then arrSourceReports(Loop2, 2) = Chr(9)
CreateSchemaIni fileSource, arrSourceReports(Loop2, 2)
Dim strRevisedQuery As String
If strRevisedQuery = vbNullString Then
strRevisedQuery = Replace(strQuery, "from " & strSourceReportTitle, "from " & fileSource.Name)
Else
strRevisedQuery = Replace(strRevisedQuery, "from " & strSourceReportTitle, "from " & fileSource.Name)
End If
lngPosition = lngEndPosition
Else
lngPosition = Len(strQuery) + 1
End If
Loop
GetRevisedQueryWithFileAliasesReplacedWithTrueFileNames = strRevisedQuery
End Function
CreateSchemaIni
Private Sub CreateSchemaIni(ByVal fileReport As Scripting.File, ByVal strDelimiter As String)
Dim intSystemFileNumber As Integer
intSystemFileNumber = FreeFile()
On Error GoTo ErrorHandler
Open fileReport.ParentFolder.Path & Application.PathSeparator & "Schema.ini" For Output As #intSystemFileNumber
Print #intSystemFileNumber, "[" & fileReport.Name & "]"
Print #intSystemFileNumber, "Format=Delimited(" & strDelimiter & ")"
Close #intSystemFileNumber
Exit Sub
ErrorHandler:
Select Case True
Case InStr(1, Err.Description, "Path/File Access Error", vbTextCompare) > 0
Dim strStandardQueryDebugLogPath As String
strStandardQueryDebugLogPath = fileReport.ParentFolder.Path & Application.PathSeparator & "strQuery.txt"
MsgBox strStandardQueryDebugLogPath & " was inaccessible. Creating log in same folder where your copy of the Mass Queryer is saved instead."
Open Left(ThisWorkbook.Path, InStrRev(ThisWorkbook.Path, Application.PathSeparator, , vbTextCompare)) & "strQuery.txt" For Output As #intSystemFileNumber
Print #intSystemFileNumber, "[" & fileReport.Name & "]"
Print #intSystemFileNumber, "Format=Delimited(" & strDelimiter & ")"
Close #intSystemFileNumber
Exit Sub
Case Else
MsgBox "Creating a query debug log has failed with the following error message: " & Err.Number & ": " & Err.Description
On Error GoTo 0
Resume
End Select
End Sub

Answer 1

With #Comintern's help, I was able to see that I made a silly mistake having nothing to do with the question title in actuality. You can see above that my CreateSchemaIni method was creating and then overwriting the Schema.ini file for each csv I was querying rather than creating and then appending to it. By changing that method to use Open For Append instead of Open For Output, the problem was solved.