CREATE TABLE particles (
   particle_diameter REAL, 
   particle_speed REAL
);
INSERT INTO particles VALUES
   (0.35, 0.74), 
   (0.57, 2.63), 
   (0.27, 1.05), 
   (0.65, 2.33);

WITH speed_series AS (
   SELECT generate_series(-1, 19.8, 0.2) AS speed_from
), speed_range AS (
   SELECT speed_from, (speed_from + 0.2) AS speed_to FROM speed_series
), diameter_series AS (
   SELECT generate_series(0, 9.8, 0.2) AS diameter_from
), diameter_range AS (
   SELECT 
      diameter_from, (diameter_from + 0.2) AS diameter_to, speed_from, speed_to
   FROM diameter_series, speed_range
)
SELECT
   diameter_from,
   diameter_to,
   speed_from,
   speed_to,
   (SELECT 
       COUNT(particle_diameter) 
    FROM particles
    WHERE particle_diameter BETWEEN diameter_from AND diameter_to
    AND particle_speed BETWEEN speed_from AND speed_to
   )
FROM diameter_range;

我会在这里尝试使用width_bucket()或floor()函数：
    with b as (
      select width_bucket(particle_diameter, 0, 10, 50) pd,
             width_bucket(particle_speed, -1, 20, 105) ps
      from particles)
    select pd * .2 - .2 diam_from, pd * .2 diam_to, 
           ps * .2 - 1.2 speed_from, ps * .2 - 1 speed_to,  
           count(1) cnt 
    from b group by pd, ps
当然，如果你需要这些零行，你可以与生成的序列连接：
    with b as (
      select width_bucket(particle_diameter, 0, 10, 50) pd,
             width_bucket(particle_speed, -1, 20, 105) ps
      from particles)
    select d diam_from, d+.2 diam_to, s speed_from, s+.2 speed_to, coalesce(t.cnt, 0) cnt 
    from (select generate_series(0, 9.8, 0.2)) as dm(d)
    cross join (select generate_series(-1, 19.8, 0.2)) AS sp(s)
    left join (
        select pd * .2 - .2 diam_from, ps * .2 - 1.2 speed_from, count(1) cnt 
        from b group by pd, ps) t
      on dm.d = t.diam_from and sp.s = t.speed_from
[dbfiddle demo](https://dbfiddle.uk/k1zekvTd)