python mysql在只有一个变量时插入语法错误

I'm using Python 2, if that matters for this issue. I'm playing with mysql.connector as a learning exercise, and had built some working inserts, then came across an odd (to me) problem--I'm sure I'm doing something wrong that is simple. I was inserting into two columns for a few tables, something like the first example, below; when I had a case where I was inserting into just one column, I got a syntax error. I'm using Python 2, if that matters for this is