Scope Resolution Operator (Transact-SQL)
The scope resolution operator :: provides access to static members of a compound data type. A compound data type is one that contains multiple simple data types and methods.
Examples
The following example shows how to use the scope resolution operator to access the GetRoot() member of the hierarchyid type.
DECLARE @hid hierarchyid;
SELECT @hid = hierarchyid::GetRoot();
PRINT @hid.ToString();
Here is the result set.
/