I work with basic SQL a lot and the best way I learned any was just to do some. Get a sample database, keep a quick reference
like this one at hand, and just set yourself little goals. Start small; I want all the vegetables from this food table. Now I only want vegetables that expire before a certain date. Now also show me red vegetables from this table and show me their corresponding nutrition values from a separate table. That kinda thing.
Better yet, build a database yourself of things you actually care about, like games. We did caravan holidays in university and it bored me to tears. Putting your own game catalogue into a database is a great way to learn the ins and outs of what SQL does because you care about what's going in it.
