SQLite Tutorial http://prdownloads.sourceforge.net/souptonuts/README_sqlite_tutorial.html?download
This article explores the power and simplicity of sqlite3, first by starting with common commands and triggers, then the attach statement with the union operation is introduced in a way that allows multiple tables, in separate databases, to be combined as one virtual table, without the overhead of copying or moving data. Next, the simple sign function and the amazingly powerful trick of using this function in SQL select statements to solve complex queries with a single pass through the data is demonstrated, after making a brief mathematical case for how the sign function defines the absolute value and IF conditions. This is a working document to help educate the community. It will always be GPL or Public domain. I am open to comments for suggestions. Regards, Mike Chirico
