JOIN by closer value to key - sql

Question

With the following sample data:
WITH values AS (
SELECT
1 AS shard,
2008 AS year,
1 AS value
UNION ALL
SELECT
1 AS shard,
20012 AS year,
2 AS value
UNION ALL
SELECT
2 AS shard,
2011 AS year,
3 AS value
UNION ALL
SELECT
2 AS shard,
1998 AS year,
4 AS value
UNION ALL
SELECT
2 AS shard,
2001 AS year,
5 AS value
UNION ALL
SELECT
4 AS shard,
1990 AS year,
6 AS value
ORDER BY year
),
data AS (
SELECT
1 AS id,
1 AS shard,
2010 AS year
UNION ALL
SELECT
1 AS id,
2 AS shard,
2000 AS year
UNION ALL
SELECT
1 AS id,
3 AS shard,
1990 AS year
UNION ALL
SELECT
2 AS id,
1 AS shard,
2010 AS year
UNION ALL
SELECT
2 AS id,
2 AS shard,
2000 AS year
UNION ALL
SELECT
2 AS id,
3 AS shard,
1990 AS year
)
I want to join my data collection with the values stored in values collection. Data has an id which differentiates each process, so I want to perform the JOIN for each id. Also, the JOIN has a double mapping key, which are the shard and year fields. I want to retreive, for each entry on my data, the value of the CLOSER year in my values collection which matches its shard attribute.
I have come up with the piece of code, but it is not working as expected as it doesn't consider the values.shard field, and it matches every year no matter the shard they are on.
SELECT *
FROM (
SELECT
data.id,
data.year,
values.year AS closer_year,
ABS(data.year - values.year) AS diff,
values.value,
ROW_NUMBER() OVER (PARTITION BY data.id, data.shard ORDER BY ABS(data.year - values.year)) AS rn
FROM data, values
)
WHERE rn = 1
For the sample data, the expected output should be:
id year closer_year diff value rn
1 2010 2008 2 1 1
1 2000 2001 1 5 1
1 1990 null null null 1
2 2010 2008 2 1 1
2 2000 2001 1 5 1
2 1990 null null null 1
What am I missing?

Answer 1

I found what I was missing just after posting the question. I will answer it in case anyone has a similar use case.
When rereading the text, I noticed that the "match the shard" property I was missing was indeed a left join, so rewriting the query like this solved the problem:
SELECT *
FROM (
SELECT
data.id,
data.year,
values.year AS closer_year,
ABS(data.year - values.year) AS diff,
values.value,
ROW_NUMBER() OVER (PARTITION BY data.id, data.shard ORDER BY ABS(data.year - values.year)) AS rn
FROM data
LEFT JOIN values
ON data.shard = values.shard
)
WHERE rn = 1