How does this pic show that Elon Musk doesnt know SQL?

I'm a tech interested guy. I've touched SQL once or twice, but wasn't able to really make sense of it. That combined with not having a practical use leaves SQL as largely a black box in my mind (though I am somewhat familiar with technical concepts in databasing).

With that, I keep seeing [pic related] as proof that Elon Musk doesn't understand SQL.

Can someone give me a technical explanation for how one would come to that conclusion? I'd love if you could pass technical documentation for that.