On: Google results for PHP tutorials contain SQL injec...

[jussij]

Back in the late 80s and early 90s many people learned to code from a book.

You would just study the code samples found in those books.

[hnick → jussij]

Or the existing code on your machine or local documentation. I learned quite a bit of QBASIC from reading nibbles.bas and gorillas.bas and the editor's own help was extensive.