SQL with no matches found causes MsgBox - ms-access

Question

My form takes the data the user entered, constructs a SQL statement and returns the results. I would like to have a message box pop up when there are no matches found.
My current code/idea:
If qdf.sql = 0 Then
MsgBox "No clients matching your information." & _
vbCrLf & "have been found. Please try again." & _
, vbCritical, "No Matches"
Else
DoCmd.OpenForm "frmSearchResults"
Me.Visible = False
End If
I'm having trouble figuring out the correct syntax for if qdf.sql = 0 .
UPDATE: Full query
Private Sub cmdSearch_Click()
'On Error GoTo cmdSearch_Click_err
Dim db As Database
Dim strSQL As String
Dim rs As DAO.Recordset
Dim qdf As QueryDef
Dim strClientID As String
Dim strLastName As String
Dim strFirstName As String
Dim strDOB As String
Set db = CurrentDb
Set rs = db.OpenRecordset(qdf.sql)
' call QueryCheck module to determine if query exists
If Not QueryExists("qrySearch") Then
Set qdf = db.CreateQueryDef("qrySearch")
Else
Set qdf = db.QueryDefs("qrySearch")
End If
' handle nulls in the user's entries
If IsNull(Me.txtClientID.Value) Then
strClientID = " Like '*' "
Else
strClientID = "='" & Me.txtClientID.Value & "' "
End If
If IsNull(Me.txtLastName.Value) Then
strLastName = " Like '*' "
Else
strLastName = " Like '" & Me.txtLastName.Value & "*' "
End If
If IsNull(Me.txtFirstName.Value) Then
strFirstName = " Like '*' "
Else
strFirstName = " Like '*" & Me.txtFirstName.Value & "*' "
End If
If IsNull(Me.txtDOB.Value) Then
strDOB = " Like '*' "
Else
strDOB = "='" & Me.txtDOB.Value & "' "
End If
strSQL = "SELECT Clients.* " & _
"FROM Clients " & _
"WHERE Clients.clientid" & strClientID & _
"AND Clients.namelast" & strLastName & _
"AND Clients.namefirst" & strFirstName & _
"AND Clients.birthdate" & strDOB & _
"ORDER BY Clients.namelast,Clients.namefirst;"
Debug.Print strSQL
' check to see if the results form is open and close if it is
DoCmd.Echo False
If Application.SysCmd(acSysCmdGetObjectState, acForm, "frmSearchResults") = acObjStateOpen Then
DoCmd.Close acForm, "frmSearchResults"
End If
' run SQL statment
qdf.sql = strSQL
' check for no matches found
If rs.RecordCount = 0 Then
MsgBox "No clients matching your information were found." & _
vbCrLf & "Please search again.", vbInformation, "No Matches"
Else
DoCmd.OpenForm "frmSearchResults"
Me.Visible = False
End If
'cmdSearch_Click_exit:
' DoCmd.Echo True
' Set qdf = Nothing
' Set db = Nothing
'Exit Sub
'cmdSearch_Click_err:
' MsgBox "An unexpected error has occurred." & _
' vbCrLf & "Please note of the following details and contact the EIIS support desk:" & _
' vbCrLf & "Error Number: " & Err.Number & _
' vbCrLf & "Description: " & Err.Description _
' , vbCritical, "Error"
' Resume cmdSearch_Click_exit
End Sub

Answer 1

The reason that If qdf.sql = 0 then won't perform a proper check is that qdf contains the information about your query such as the SQL text that you are checking in that statement but not the results.
To get the results of the query you need to assign it to a Recordset after you have build your query. So first build your query and then assign it to the record set.
Dim db as DAO.Database
Set db = CurrentDb
Dim qdf as DAO.Querydef
Set qdf = db.CreateQueryDef("qrySearch")
Dim rs as DAO.Recordset
Set rs = CurrentDb.OpenRecordset(qdf.sql)
You can then check what your record set has returned.
If rs.RecordCount = 0 then
So where you have your line ' run SQL statment you would want to place the Set rs line.

Answer 2

If you have any ADO experience you can use something like
dim strSQL as String
dim conn as Connection
dim cmd as Command
dim rs as Recordset
(set up connection/command here)
cmd.commandtext = (your select query)
set rs = Command.execute
if rs.eof then
(or if rs.recordcount = 0 however returning a recordcount requires the correct cursortype - usually adOpenStatic - to be used)
'msgbox no match
else
'do stuff
If any of this is alien, then post your actual query and I'll try and give you the code in full. Good luck!