What tools do you use today to work with complex semi-structured data?

https://www.snowflake.com/wp-content/uploads/2015/06/Snowflake_Semistructured_Data_WP_1_0_062015.pdf

Ja, the best tool is the one that you know best.
It is really hard to visualize the "complex semi-structured data" part, since in my experience it can be a really messy and even disturbing combination of origins, creators, db designs and platforms.
I've been using various tools along my path in IT, but when working with complex semi structured data origins, there are no tools powerful enough to handle that, so I usually end up creating my own SQL queries, on any IDE.
I usually create a query to serve me as a template, and then start detailing it with the complex details.
At worst, you need to create queries on different platforms and then call them from a unifying interfase.
Hope this helps