mode
Takes the most common non-null grouped value.
mode(xs:list) -> anyDescription
The mode function returns the most frequently occurring non-null value in
xs.
xs: list
The values to evaluate.
Examples
Find the mode of values
from {x: 1}, {x: 1}, {x: 2}, {x: 3}
summarize mode_value=mode(x)
{mode_value: 1}