The details reg querying can be found here. https://www.zoho.com/catalyst/help/zcql.html#Join

Joins based on relationships are supported.

And also this tutorial is helpful to get things started

https://www.zoho.com/catalyst/help/tutorials/alcity/introduc...

It seems queries are constructed from strings?

https://www.zoho.com/catalyst/sdk/nodeJS-sdk/zcql_execute.ht...

What about injections, escaping queries, etc?