Below is the query which will return you TKB subject by views sorting.
SELECT subject FROM messages WHERE conversation.style='tkb' ORDER BY metrics.views DESC
Here is the documentation https://community.lithium.com/t5/Developer-Documentation/bd-p/dev-doc-portal?section=commv2&collection=messages#constraints-conversation.style
If you just want to get all the tkbs from Boersenlexikon board. You don't need to add conversation.style either.
SELECT subject FROM messages WHERE board.id='Boersenlexikon' ORDER BY metrics.views DESC
