Alan, I think its up to you what you consider a simple example.
The camel-jdbc is very simple as you don't need to write code. Though its also a bit limited, and when you need a bit more, then maybe a bean using spring jdbc template is also a simple solution (for people okay with writing a bit of code).
The camel-sql is a bit special IMHO as you have the query in the uri, which maybe is not so nice for bigger queries. Though you can set the SQL query as a header as well. I think camel-sql uses prepared statements so maybe its overall better.