How does one count/sum RANGES of data values in a column?

A value x will be between values y and z if GREATEST(x, y) = LEAST(x, z). Look at this example:

select f2,

sum(decode(greatest(f1,59), least(f1,100), 1, 0)) "Range 60-100",

sum(decode(greatest(f1,30), least(f1, 59), 1, 0)) "Range 30-59",

sum(decode(greatest(f1, 0), least(f1, 29), 1, 0)) "Range 00-29"

from my_table

group by f2;

For equal size ranges it might be easier to calculate it with DECODE(TRUNC(value/range), 0, rate_0, 1, rate_1, ...). Eg.

select ename "Name", sal "Salary",

decode( trunc(f2/1000, 0), 0, 0.0,

1, 0.1,

2, 0.2,

3, 0.31) "Tax rate"

from my_table;