A null value means that data is unavailable. Empty text is still text and may need separate handling with Len or Trim.
IsNull
Checks whether a value is null.
- Syntax:
IsNull(value)
- Requires: any one value.
- Returns: Boolean.
- Best for: choosing a fallback or avoiding work that requires a value.
Returns the first non-null value.
- Syntax:
Nz(value) or Nz(value, fallback[, fallback...])
- Requires: one or more values. When fallbacks are supplied, all non-null values must have the same type.
- Returns: the first non-null value. With one null argument, returns empty text; if every supplied fallback is null, returns
null.
- Best for: defaults that preserve the intended value type.
Nz does not treat empty text, zero, or false as null.
