As I outlined already, the Toolset Custom Fields are just normal WordPress Custom Post Fields.
The one you look for to get related posts is the only specific one:
_wpcf_belongs_{parent-post-type-slug}_id
All Custom Post Fields created by Toolset will as well have a special prefix:
The question of this Ticket was how to get related Posts with that Plugin.
The result is that one must fluently know SQL to achieve this.
Toolset's purpose is not to teach SQL or even encouraged to use it.
Its purpose is the exact opposite:
Avoid any form of coding.
With Toolset, it is possible to create Tables using the Views Plugin, this is the way we have to suggest.
I fear, for further customization of that SQL, given the information above, is subject to Custom Code.
With the information, we provided it is possible to create tables with that Plugin.
But it seems, the plugin is not able to build the Query with the GUI they provide.
Hence, SQL knowledge is required.
Or you could ask that Plugin's Support, how to create a Query with the software when your Custom Fields are:
- as outlined above
This would be the same problem if you would not use Toolset.
Assume you create a Custom Post Type with a hidden Custom Field, and a visible Custom Field using a Prefix.
That is usual in WordPress, nothing that requires any addon plugins actually.
Stil, with the Table Plugin you could not create the query unless you have advanced SQL knowledge, or they maybe have some settings to get hidden fields, which we oversaw.
However, this is not related to Toolset in this aspect.
Do you agree?