Question

Here is my table example:

LETTER  NUMBER
a   1
a   2
a   4
b   1
b   2
b   3
c   1
c   2
c   3
d   1
d   2
d   3
e   1
e   2
e   3

The result I want:

LETTER  NUMBER
a   2
b   2
c   2
d   2
e   2

The highest number that matches an ‘a’ is 4, while it’s 3 for the other letters. However, the highest letter they all have in common is 2. That is why the result table has 2 for the NUMBER.

Does anyone know how I can accomplish this?

Answer 1

Let’s call your table l. Here’s a horribly inefficient solution:

select l.LETTER, max(l.NUMBER)
from l
where
    (select count(distinct LETTER) from l)
  = (select count(distinct l2.LETTER) from l as l2 where l2.NUMBER = l.NUMBER)
group by l.LETTER;

Kind of a mess, huh?