Nz
Replaces a Null value with the specified replacement value.
Syntax: Nz( value [ , valueIfNull ] )
- value
- required A Variant to check for Null.
- valueIfNull
- optional A Variant to return if value is Null. If omitted, Nz returns Empty.
The return type is Variant.
Nz is useful for handling expressions that may evaluate to Null — most commonly, fields read from a database recordset where a column permits Null. Unlike a direct comparison with Null (which itself yields Null), Nz returns a usable substitute value.
If value is anything other than Null, Nz returns value unchanged.
Note
The function originated in Microsoft Access. twinBASIC provides it as a built-in so the same idiom can be used outside of an Access host.
Example
This example uses Nz to substitute the string "Unknown" for a recordset field that may be Null.
Dim customerName As Variant
customerName = recordset.Fields("Name").Value
MsgBox "Customer Name: " & Nz(customerName, "Unknown")