StreamSQL is the TIBCO StreamBase text-based language for defining complex event processing applications. StreamSQL is an alternative to the graphical EventFlow language. StreamSQL and EventFlow are equivalent but not identical languages, and each has a few features and conveniences that the other lacks. Each language has its strengths and best use cases.
Many new users make the assumption that StreamSQL is the true language underlying EventFlow applications, but this assumption is incorrect. EventFlow applications are defined in an XML syntax that also serves to define an EventFlow application's presentation in StreamBase Studio. By contrast, StreamSQL is its own language that draws from and extends standard SQL. StreamBase Server accepts applications defined in either EventFlow XML or in StreamSQL, and compiles each application type independently to the same executable code.
You can convert an EventFlow application to StreamSQL (with some restrictions), but not the reverse. Converting an existing EventFlow application to StreamSQL is probably the best approach to learning StreamSQL.