COMPREHENSION SUPPORT OF SQL STATEMENT USING DOUBLE-TREE STRUCTURE Topics: Authoring Tools and Content Development; Educating the Educators; e-Learning Hardware and Software; Pedagogy Enhancement with E-Learning; Synchronous and Asynchronous Learning In Proceedings of the 3rd International Conference on Computer Supported Education - Volume 1: CSEDU, 318-323, 2011 , Noordwijkerhout, Netherlands