SQL - Compare 2 different ranges of date - sql

Question

The table has these columns:
DATA, CODE and so on..
I need to display two different ranges of date and its code like:
|data|code|data2|code|
My query is:
SELECT DATA,CODE
FROM people
WHERE DATA >= ${data1} AND DATA <= ${data2}
GROUP BY DATA
ORDER BY DATA
What I did was trying to do 2 queries with differents variable but both return always the same range of data.
So I did something like:
SELECT DATA,CODE
FROM people
WHERE DATA >= ${d1} AND DATA <= ${d2}
GROUP BY DATA
ORDER BY DATA
and try to assign 4 differents date in order to get 2 ranges of period. Let's imagine data1='01-01-2001' and data2='31-12-2001' while d1='01-01-2002' and d2='31-12-2002'.
When I assigned the dates, both return only the last range.
So instead of getting |2001|code|2002|code| I've got |2002|code|2002|code|
I need for comparison, so I want to compare every day of the year 2001 on the left and with every day of the year 2002 on the right.

Answer 1

Using the bind variables :start1 and :end1 as the bounds for the first range and :start2 and :end2 as the bounds for the second range:
SELECT d1.data AS data1,
d1.code AS code1,
d2.data AS data2,
d2.code AS code2
FROM (
SELECT data,
code,
ROW_NUMBER() OVER ( ORDER BY data ) AS rn
FROM people
WHERE data BETWEEN :start1 AND :end1
) d1
FULL OUTER JOIN
(
SELECT data,
code,
ROW_NUMBER() OVER ( ORDER BY data ) AS rn
FROM people
WHERE data BETWEEN :start2 AND :end2
) d2
ON ( d1.rn = d2.rn )