I remember years ago, when a friend launched his now defunct site without asking some help from developers (he's an undergrad at that time), his site(blog) has been plagued with different hackers. All the data has been deleted, or can I say manipulated? Later we found out that the hackers used this so-called sql injection. I've read from an article from this site http://www.webhostingsearch.com/articles/sql-injection-attack-protect-your-data.php that even though you have SSL certificates, your blog is still subjected to SQL injections.
If that's the case, what can be done to avoid (or maybe minimize) it?