Joe Celko's SQL for Smarties, 3rd Edition

23.3. The Median

The median is defined as the value for which there are just as many cases with a value below it as above it. If such a value exists in the data set, this value is called the statistical median by some authors. If no such value exists in the data set, the usual method is to divide the data set into two halves of equal size such that all values in one half are lower than any value in the other half. The median is then the average of the highest value in the lower half and the lowest value in the upper half, and is called the financial median by some authors. The financial median is the most common term used for this median, so we will stick to it. Let us use Date’s famous Parts table, from several of his textbooks (Date 1983, ...