Count with Case Select in Oracle - oracle

Question

I have the following query:
SELECT t.range,
Count(*)
FROM (
SELECT CASE
WHEN creditscore BETWEEN 300
AND 499
THEN '[300, 499]'
WHEN creditscore BETWEEN 500
AND 699
THEN '[500, 699]'
WHEN creditscore BETWEEN 700
AND 850
THEN '[700, 850]'
END AS range
FROM customer
) T
GROUP BY t.range;
Which gives me the following :
CS range COUNT(*)
---------- ----------
[700, 850] 7
[500, 699] 13
I want the following output:
CS range COUNT(*)
---------- ----------
[300, 499] 0
[500, 699] 13
[700, 850] 7
Can anyone help me out?
UPDATE
I executed the code the Justin provided. It gives me the following:
DESCRIPTIO COUNT(*)
---------- ----------
[300, 499] 1
[700, 850] 7
[500, 699] 13
SQL> SELECT COUNT(*) FROM customer where creditscore BETWEEN 300 AND 499;
COUNT(*)
----------
0

Answer 1

One option would be to do something like
WITH ranges AS (
SELECT '[300, 499]' description, 300 min_val, 499 max_val FROM dual
UNION ALL
SELECT '[500, 699]' description, 500 min_val, 699 max_val FROM dual
UNION ALL
SELECT '[700, 850]' description, 700 min_val, 850 max_val FROM dual
)
SELECT r.description, count(creditscore)
FROM ranges r
LEFT OUTER JOIN customer c
ON (c.creditscore BETWEEN r.min_val AND r.max_val)
GROUP BY r.description
Normally, you'd want to set up a permanent table with your ranges in case someone wants to add or modify them in the future. But you can hard-code the ranges in your query like I do here.

Answer 2

You can use unpivot in this case.
Your answer-
Select * From
(
Select Sum(Col1) "[300, 499]", Sum(Col2) "[500, 699]", Sum(Col3) "[700, 850]"
From (
Select Case
When Creditscore Between 300
And 499
Then 1 Else 0 End As Col1,
Case When Creditscore Between 500
And 699
Then 1 Else 0 End Col2,
Case When Creditscore Between 700
And 850
Then 1 Else 0 End Col3
From Customer
)
)
Unpivot
(
"Count"
For
"Description" In ("[300, 499]", "[500, 699]", "[700, 850]")
);
Result -
Description Count
[300, 499] 0
[500, 699] 4
[700, 850] 3