That's Dana White stomping all over Jake Paul's dream of fighting Conor McGregor -- telling TMZ Sports there's a "zero percent" chance that fight ever happens.

Remember, Jake Paul called out Conor McGregor after knocking  Nate Robinson out cold in the 2nd round of their Nov. 28 boxing match.

Jake later told TMZ Sports his team reached out to Conor's manager to begin talks about a possible fight -- and added, "I'm going in there to f**k Conor McGregor up."

And, with Jake's big bro, Logan Paul, scoring a boxing exhibition with Floyd Mayweather, seems anything's possible these days.

While Dana says he applauds both Paul bros for "injecting themselves into the fight world" ... he makes it pretty clear when it comes to fighting skill, they're not even on the same planet as Conor and Floyd.

"There's a market for these kinda fights. It's just not what I do," White says.

"There will be a day when Conor McGregor could do these types of fights and make a bunch of money," White adds ... but it ain't happening any time soon.