IN operator form to check belonging to hierarchy

You can check if a catalog belongs to specific hierarchy. IN HIERARCHY operator will return TRUE if the left-side expression value is a reference to a catalog item and is included in the right-side value array or hierarchically belongs to some group which is included in this array:

Example:

// As the Group parameter query receives reference
// to some Nomenclature catalog group.

SELECT
   Catalog.Nomenclature.Description

WHERE
  Catalog.Nomenclature.Ref IN HIERARCHY (&Group)

Query result can act as a value array that is checked for matching. In that case you need to specify a query description to the right of IN operator.

Example:

SELECT
   Catalog.Nomenclature.Description

WHERE
Catalog.Nomenclature.Ref IN HIERARCHY
   ( 
SELECT
        Catalog.Nomenclature.Ref
WHERE
         Catalog.Nomenclature.Description = "Clothes"
   )