Given an RGB value what would be the best way to find the closest match in the database?

Question

I have a rgb value and if it doesn\'t exist in the color table in my database I need to find the closest color. I was thinking of comparing all values and finding the diffe

Answer 1

One step better than average is nearest square root:

((delta red)^2 + (delta green)^2 + (delta blue)^2)^0.5

This minimizes the distance in 3D color space.

Since a root is strictly increasing, you can search for the maximum of the square instead. How you express this in SQL would depend on which RDBMS you're using.