VBA to query field contents in CSV - vba

Question

I'm struggling with ADO connections/recordsets.
My problem statement is: a function that will return the first value of a chosen field, in a chosen .csv file.
I am doing this to identify variably-named .csv files before adding the data to the relevant tables in a database. I am making the assumption that this field is always present and that either it is consistent throughout the file, or only relevant ones are grouped (this is controlled higher up the chain and is certain enough).
My code is being run as part of a module in an MS Access database:
Public Function GetFirstItem(File As Scripting.File, Field As String)
Dim Conn As ADODB.Connection, Recordset As ADODB.Recordset, SQL As String
Set Conn = New ADODB.Connection
Set Recordset = New ADODB.Recordset
'Microsoft.ACE.OLEDB.16.0 / Microsoft.Jet.OLEDB.4.0
Conn.ConnectionString = "Provider=Microsoft.ACE.OLEDB.16.0;Data Source=""" & File.ParentFolder & _
"""; Extended Properties=""text;HDR=Yes;FMT=Delimited;"";"
SQL = "SELECT " & Field & " FROM """ & File.Name & """ LIMIT 1"
Debug.Print Conn.ConnectionString
Debug.Print SQL
Conn.Open
Recordset.Source = SQL
Recordset.ActiveConnection = Conn.ConnectionString
Recordset.Open
Recordset.MoveFirst
'GetFirstItem = Recordset!Questionnaire
Recordset.Close
Conn.Close
Set Recordset = Nothing
Set Conn = Nothing
End Function
ConnectionString = Provider=Microsoft.ACE.OLEDB.16.0;Data Source="D:\Documents\Jobs\TestPath"; Extended Properties="text;HDR=Yes;FMT=Delimited;";
Field = Questionnaire
SQL = SELECT Questionnaire FROM "test.csv" LIMIT 1
I get an error on Recordset.Open of:
This may be (is probably) down to a complete lack of understanding of how ADO connections/recordsets work. I have tried sans-quotes and it complains about a malformed FROM expression. Additionally, once this hurdle is overcome I am unsure of the syntax of how to return the result of my query. If there is a better way of doing this I am all ears!
Thanks.

Answer 1

In Access you don't need ADO library to query a CSV file:
Public Function GetFirstItem(File As Scripting.File, Field As String) As String
Dim RS As DAO.Recordset, SQL As String
SQL = "SELECT TOP 1 [" & Field & "]" _
& " FROM [" & File.Name & "]" _
& " IN '" & File.ParentFolder & "'[Text;FMT=CSVDelimited;HDR=Yes];"
Debug.Print SQL
Set RS = CurrentDb.OpenRecordset(SQL)
GetFirstItem = RS(0)
RS.Close
Set RS = Nothing
End Function
Usage:
?GetFirstItem(CreateObject("Scripting.FileSystemObject").getfile("c:\path\to\your\file.csv"), "your field")