Deprecated. Don't use for new development and try to migrate existing uses.
This function is only intended to be used with the grid component and not elsewhere.
It takes two strings containing comma separated lists of column ordinals and joins them together.
Returns a single comma separated list. If the same ordinal is in both parameter lists, it will still only be returned once. If the same column have different sorting options in either list (asc and desc) then the sorting option in the first list will be used.