search for: sqlzoo

Hi, I was lucky enough to learn ruby a bit before starting to learn rails. That has helped quite a bit. Unfortunately, my knowledge of SQL and databases in general started from zero when approaching rails, and I find that trying to "get" database stuff from the context of rails books and documentation is holding me back. Can anyone recommend a free online pdf or website that will

...p the dsn correctly & connected to it (see above), and (b) you know something of database querying language. I don't want to get bogged down by any details here, but I find this website to have good tutorials (although horrible search capabilities or reference-style documentation): http://sqlzoo.net/ Final point on querying: with an accidentally typo, your query can go from 2,000 rows long to 2,000,000,000 rows long (e.g., if you perform a join incorrectly). So it's sometimes worthwhile to make your first query a "count(*)" query so that you know how many rows of data you&...