Remove CROSS JOIN LATERAL from postgres query that spans many to many - sql

Question

I have the following three tables (many to many):
Location
+====+==============+===+===+=============+
| id | coord_system | x | y | last_update |
+====+==============+===+===+=============+
| | | | | |
+----+--------------+---+---+-------------+
Mapping
+=============+============+
| location_id | history_id |
+=============+============+
| | |
+-------------+------------+
History
+====+=======+======+
| id | speed | date |
+====+=======+======+
| | | |
+----+-------+------+
The location table represents physical x, y locations within a specific coordinate system. For each x, y location at least one row in the history table exists. Each row in the history table can point to multiple rows in the location table.
Important to note is that (coord_system, x, y) is indexed and is unique. I don't think it makes a difference but all ids and coord_system are UUIDs. In the code examples below I will use letter to make it easier to read. The location and history have additional columns, but do not change the scope of the question. The last_update column on the location table should match the date column on the History table (I come back to this later in the post).
The goal is to fetch the most recent history row for a range of (coor_system, x, y). Currently this is done with a CROSS JOIN LATERAl, like
SELECT *
FROM location loc
CROSS JOIN LATERAL
(SELECT *
FROM history hist
LEFT JOIN mapping map ON hist.id = map.history_id
WHERE map.location_id = loc.id
ORDER BY date DESC limit(1)) AS records
WHERE loc.coord_system = '43330ccc-3f42-4f05-8ec5-18cb659bfd2d'
AND (x >= 403047
AND x <= 404047)
AND (y >= 16451337
AND y <= 16452337);
For this specific range of x, y and coord_system the query takes ~25 seconds to run and returns 182 351 rows.
I am not extremely experienced in SQL, but thought that the goal of this query could also be achieved using a regular join. If I do a join across the three tables, with the same x, y and coord_system "filters" it takes about 2 seconds and returns ~3 million rows. I tried to be clever and use the dates to prune down the result:
SELECT *
FROM history hist
RIGHT JOIN mapping map ON hist.id = map.history_id
RIGHT JOIN location loc ON loc.id = map.location_id
WHERE loc.coord_system = '43330ccc-3f42-4f05-8ec5-18cb659bfd2d'
AND (x >= 403047
AND x <= 404047)
AND (y >= 16451337
AND y <= 16452337)
AND location.last_update = hist.date
This got very close to the same result as the original query. The result was 182 485 rows in ~3 seconds. Unfortunately the result needs to be exactly the same. I am guessing I made a logical mistake in the query I made and came here hoping someone can point it out.
My question is: is there a clever way that will allow a join to take only the rows that have the "newest" date from the history.date column? As is expected I am trying to make the query run as quickly as possible while maintaining the correct result set.
In the table below I show a toy example of the join and the results I would expect (marked in the "return_row" column).
+=============+==============+===+===+=============+============+============+=======+============+============+
| location.id | coord_system | x | y | location_id | history_id | history.id | speed | date | return_row |
+=============+==============+===+===+=============+============+============+=======+============+============+
| 0 | a | 1 | 1 | 0 | 0 | 0 | 3.0 | 2020/10/31 | * |
+-------------+--------------+---+---+-------------+------------+------------+-------+------------+------------+
| 0 | a | 1 | 1 | 0 | 1 | 1 | 3.1 | 2020/10/30 | |
+-------------+--------------+---+---+-------------+------------+------------+-------+------------+------------+
| 0 | a | 1 | 1 | 0 | 2 | 2 | 3.2 | 2020/10/29 | |
+-------------+--------------+---+---+-------------+------------+------------+-------+------------+------------+
| 1 | a | 1 | 2 | 1 | 3 | 3 | 3.1 | 2020/10/31 | * |
+-------------+--------------+---+---+-------------+------------+------------+-------+------------+------------+
| 1 | a | 1 | 2 | 1 | 4 | 4 | 3.0 | 2020/10/30 | |
+-------------+--------------+---+---+-------------+------------+------------+-------+------------+------------+
| 2 | a | 2 | 2 | 2 | 5 | 5 | 4 | 2020/10/31 | * |
+-------------+--------------+---+---+-------------+------------+------------+-------+------------+------------+
| 3 | b | 1 | 1 | 3 | 6 | 6 | 5 | 2020/10/1 | * |
+-------------+--------------+---+---+-------------+------------+------------+-------+------------+------------+

Answer 1

Does it work better with DISTINCT ON?
SELECT DISTINCT ON (l.id) l.id, h.date, ... -- enumerate the columns here
FROM location l
LEFT JOIN mapping m ON m.location_id = l.id
LEFT JOIN history h ON h.id = m.history_id
WHERE
l.coord_system = '43330ccc-3f42-4f05-8ec5-18cb659bfd2d'
AND l.x BETWEEN 403047 AND 404047
AND l.y BETWEEN 16451337 AND 16452337
ORDER BY l.id, h.date DESC