cartodb-4.42/lib/sql/doc/CDB_HeadsTailsBins.md

Find the breaks for N categories in a numerical column based on the Heads/Tails optimization. Below, Heads/Tails used to color based on the area of the polygons.

Using the function

We can determine the 7 most optimal breaks in a column of numerical data as follows,

SELECT CDB_HeadsTailsBins(array_agg(numeric_column), 7) FROM table_name
-- Results in an ordered array like, {7824,23492,52696,233857,666089,1001709,1638094}
-- Each break happens up to, and equal, to a number: 
-- (bin1 is less than or equal to 7824, bin2 is less than or equal to 23492, etc.)

Arguments

CDB_HeadsTailsBins(in_array, breaks)

• in_array numeric[]. A NUMERIC array of values.
• breaks int. The number of categories you want to create