Undefined function 'Nz' in expression

Question

I've Googled this error and haven't drawn up a conclusion to why I'm receiving this error. I'm trying to fill a DataGridView with some data. Here is my code.

Private Sub LoadGrid()
    Dim cmd As New OleDbCommand
    Dim dt As DataTable
    With cmd
        .CommandText = "project_master_query"
        .CommandType = CommandType.StoredProcedure
        .Connection = New OleDbConnection(My.Settings.cnnString)
    End With
    dt = GetData(cmd)
    dgvData.DataSource = dt
End Sub

Private Function GetData(ByVal cmd As OleDbCommand) As DataTable
    Dim dt As New DataTable
    Using cmd.Connection
        cmd.Connection.Open()
        dt.Load(cmd.ExecuteReader(CommandBehavior.CloseConnection))
    End Using
    Return dt
End Function

Query "project_master_query" stored within Access.

    SELECT project_master.*, location_master.LocationName,
    project_currentmilestonedef.MilestoneDefID, 
    project_currentmilestonedef.MilestoneName, project_regions.RegionName,
    owner_fullname.FullName AS OwnerFullName, designer_fullname.FullName AS DesignerFullName,
    project_issuecount.HasOpenIssues, project_updated_closedate.UpdatedCloseDate, 
    project_bonusdays.BonusDays, project_bonusdays.IsGreen, project_bonusdays.IsYellow, 
    project_bonusdays.IsRed, checklist_days_perproject_defined_1.Week1, 
    checklist_days_perproject_defined_1.Week2, checklist_days_perproject_defined_1.Week3, 
    checklist_days_perproject_defined_1.Week4, project_issueduration.ProjectIssueDurationDays, 
    project_active_status.ProjectIsOpen, project_requirement_status.RequirementStatusName, 
    priority_def.PriorityShortName
    FROM project_requirement_status 
    RIGHT JOIN (project_regions 
    RIGHT JOIN (priority_def RIGHT JOIN (location_master 
    RIGHT JOIN ((((checklist_days_perproject_defined AS checklist_days_perproject_defined_1 
    RIGHT JOIN ((((((((contacts_fullname AS designer_fullname 
    RIGHT JOIN (contacts_fullname AS owner_fullname 
    RIGHT JOIN project_master ON owner_fullname.ContactID = project_master.ContactOwner) 
    ON designer_fullname.ContactID = project_master.ContactDesigner) 
    LEFT JOIN project_issuecount 
    ON project_master.ProjectID = project_issuecount.ProjectID) 
    LEFT JOIN project_currentmilestonedef 
    ON project_master.ProjectID = project_currentmilestonedef.ProjectID) 
    LEFT JOIN project_within_benchmark_week1 
    ON project_master.ProjectID = project_within_benchmark_week1.ProjectID) 
    LEFT JOIN project_within_benchmark_week2 
    ON project_master.ProjectID = project_within_benchmark_week2.ProjectID) 
    LEFT JOIN project_within_benchmark_week3 
    ON project_master.ProjectID = project_within_benchmark_week3.ProjectID) 
    LEFT JOIN project_updated_closedate 
    ON project_master.ProjectID = project_updated_closedate.ProjectID) 
    LEFT JOIN checklist_days_perproject_defined 
    ON project_master.ProjectID = checklist_days_perproject_defined.ProjectID) 
    ON checklist_days_perproject_defined_1.ProjectID = project_master.ProjectID) 
    LEFT JOIN project_issueduration 
    ON project_master.ProjectID = project_issueduration.ProjectID) 
    LEFT JOIN project_active_status 
    ON project_master.ProjectID = project_active_status.ProjectID)    
    LEFT JOIN project_bonusdays ON project_master.ProjectID = project_bonusdays.ProjectID) 
    ON location_master.LocationID = project_master.Location) 
    ON priority_def.PriorityDefID = project_master.ProjectPriority) 
    ON project_regions.RegionID = project_master.Region) 
    ON project_requirement_status.RequirementStatusID = project_master.RequirementStatus;

As you can see there is no Nz in the query at all so I don't understand why this happening at all. The error occurs once the dt.Load is called.

Twilatwilight

Are you sure this is the query you are getting the issue with? – Orabelle

This is the only query I'm calling. LoadGrid() is called on the Loading of the application. – Twilatwilight

Answer 1

The Nz function is most likely in a view/query you are referencing in one of your many joins. You'll have to look through all of them.

As Nz() is a function of the Access application and not the Access driver, it will fail anytime you try to use it from outside the Access application. You can replace the Nz with an IIf(IsNull()) construct.

See documentation for IIf and IsNull

When put together:

Nz(expr, [valueifnull])

becomes

IIf(IsNull(expr), valueifnull, valueifnotnull)

Examples

Default: Nz(tbl.A) => IIf(IsNull(tbl.A), '', tbl.A)

With fallback: Nz(tbl.A, tbl.B) => IIf(IsNull(tbl.A), tbl.B, tbl.A)

Jitterbug

Answer 2

I've created a function to use in this case. I called it ez.

Public Function ez(ByVal vVal1 As Variant, Optional ByVal vVal2 As Variant = 0) As Variant
    If VBA.IsNull(vVal1) Or VBA.Len(vVal1) = 0 Then
        ez = vVal2
    Else
        ez = vVal1
    End If
End Function

As you can see, it goes a little further than the original function since it not only considers the second value if the first one is null but also if it is empty

Also, the default return value is 0 while with Nz is an empty string.

Specht