In VCL, it's enough to set the display format to "00-00-00' so the result in DBgrid is '00-12-34', as I expected, but in uniDBgrid it turns out to be '12-34-00', oops. ..
Actually, I can handle it in many ways, but if no one can provide a solution, that's okay, I can handle it myself, thank you for the response, good luck.