JSTL SQL tags were never meant for use in production quality applications.
Here is the top of section 10 in the JSTL spec:
Many web applications need to access relational databases as the source of dynamic
data for their presentation layer. While it is generally preferred to have database
operations handled within the business logic of a web application designed with an
MVC architecture, there are situations where page authors require this capability
within their JSP pages (e.g. prototyping/testing, small scale/simple applications,
lack of developer resources).
The JSTL SQL actions provide the basic capabilities to easily interact with relational
databases.
If you need more specific functionality or if this is part of a real app that will need to be maintained and updated over time, you'll do yourself a favor by dumping the JSTL SQL tags now and move to a proper MVC architecture that allows you to control, exactly, how your data is structured before it ever reaches the
JSP.