如何查询Oracle中列值的分布（按值范围分组）？

Question

假设在Oracle中有一个名为DISTANCES的表，该表的浮动类型列名为distance。 距离范围是[0，1000]。 我想知道距离的分布，例如，以下各个范围中有多少行：（0，10]，（10，50]，（50，100]，（100，500]，.. 。（5000，10000]。

如何建立这个SQL查询？

Answer 1

使用派生表将每个距离归入其组。 然后GROUP BY并count ：

select dist_group, count(*)
from
(
 select case when distance between 0  and 10 then '(0, 10)'
             when distance between 10 and 50 then '(10, 50)'
             ...
             when distance between 5000 and 10000 then '(5000, 10000)' end as dist_group
 from distances
)
group by dist_group

Answer 2

SELECT COUNT( CASE WHEN   0 <= distance AND distance <=   10 THEN distance END ) AS in_range_0_10,
       COUNT( CASE WHEN  10 <  distance AND distance <=   50 THEN distance END ) AS in_range_10_50,
       COUNT( CASE WHEN  50 <  distance AND distance <=  100 THEN distance END ) AS in_range_50_100,
       COUNT( CASE WHEN 100 <  distance AND distance <=  500 THEN distance END ) AS in_range_100_500,
       COUNT( CASE WHEN 500 <  distance AND distance <= 1000 THEN distance END ) AS in_range_500_1000
FROM   Distance;