For standard attributes, null values are handled identically for all data types. For dynamic attributes, you can configure whether you want a null value to be interpreted as a minimum, maximum, or average value using the dynamic attribute Default Value option.
If a sorting rule is based on a standard attribute, then null values are always added to the end of the result set, independent of the sorting direction.
Ascending values are sorted as:
1
2
3
null
null
Descending values are sorted as:
3
2
1
null
null
You can control how null values are sorted in dynamic attributes by setting the Default Value for the attribute.
Null values are sorted to the end of the result set, similar to the default behavior for standard attributes.
Null values are sorted to the middle of the result set, as though the value was the average of all values. This is useful if you have incomplete data for some products, but do not want a null value to automatically cause the product to be sorted to the end of the result set.
Null values are sorted to the beginning of the result set. This is useful if you have new products with incomplete data, such as sales figures, that you want to promote