Use google bigquery to build histogram graph

Question

How can write a query that makes histogram graph rendering easier?

For example, we have 100 million people with ages, we want to draw the histogram/buckets for age 0

Answer 1

Using a cross join to get your min and max values (not that expensive on a single tuple) you can get a normalized bucket list of any given bucket count:

select
  min(data.VAL) as min,
  max(data.VAL) as max,
  count(data.VAL) as num,
  integer((data.VAL-value.min)/(value.max-value.min)*8) as group
from [table] data
CROSS JOIN (SELECT MAX(VAL) as max, MIN(VAL) as min, from [table]) value
GROUP BY group
ORDER BY group 

in this example we're getting 8 buckets (pretty self explanatory) plus one for null VAL