How to find Euclidean Distance between query image and database images?

I want to calculate Euclidean Distance between 1000 database images and query image. I want to retrieve those images which are having minimum distance to match query image. I have calculated feature vectors such as mean, standard deviation and skewness for 1000 database images stored it in 1000 .mat files. and also i have calculated feature vector for query image. How to calculate Euclidean Distance. Please Help.