Greetings Snark Lord of The Publishing Underworld, and your Killer Yap, too:
I recently wasted my first novel on a POD press run by an idiot in his garage. (My career nitwit moment.) Thankfully, he was too incompetent to keep records, as evidenced by some of the other authors who didn't get paid. However, this also contributed to garage nitwit's downfall.
I'm now shopping my second book. Since the first one's sales were statistically insignificant - as in nobody who should have kept statistics, if only to show the IRS - should I bother mentioning this one in agent queries?
Back in the saddle after falling off a pony
Is there an ISBN?
Is there copyright registration?
Does it show up if I google your name?
If you answer no on two or more, you can keep it under your hat at the query stage. All three, and you probably never need to tell anyone outside the bar when you're regaling Miss Snark with tales of woe at the next writing conference.
If the answer is yes to two or more, better to fess up, exactly as you did here.
The reason is, if you've been published the next one isn't your debut. I can finess that if I have to but I want to know I need to rather than discovering on Page Six that the Smoking Gun loves you a lot.