Check for ranges overlapping database side with coalesce - mysql

Question

I can't figure out how to check on database side if two ranges, that can handle null values (ex. range A: null - null range B: 3 - 10), overlaps.
In this case, those two ranges overlaps because in my code null - null it's equal to -∞ and +∞ so 3 - 10 is inside -∞ - +∞.
The problem is that i need to build a query that returns all the records from my table stock_rule that have a range that overlaps with the stock_rule record that i'm trying to create.
If the count is major than zero then i can't save the record.
I'm trying to achieve that using COALESCE function (MySQL 8.0) in this way:
COALESCE(rule.min_price, 0)<=COALESCE(:minPrice, rule.min_price,0) AND
COALESCE(rule.max_price, 0)<=COALESCE(:minPrice, rule.max_price, 0) AND
COALESCE(rule.min_price, 0)<=COALESCE(:maxPrice, rule.min_price,0) AND
COALESCE(rule.max_price, 0)<=COALESCE(:maxPrice, rule.max_price, 0) AND
COALESCE(:minPrice, 0)>=COALESCE(rule.min_price, :minPrice, 0) AND
COALESCE(:maxPrice,0)<=COALESCE(rule.min_price, :maxPrice, 0) AND
COALESCE(:minPrice,0)>=COALESCE(rule.max_price, :minPrice, 0) AND
COALESCE(:maxPrice, 0)<=COALESCE(rule.max_price, :maxPrice, 0)

Answer 1

I guess something like this would work...
DROP TABLE ranges;
CREATE TABLE ranges
(id seriAL PRIMARY KEY
,range_start INT NULL
,range_end INT NULL
);
INSERT INTO ranges VALUES
(1,NULL,NULL),
(2,3,10),
(3,12,NULL),
(4,NULL,20),
(5,10,11);
SELECT *
FROM ranges x
JOIN ranges y
ON y.id <> x.id
AND COALESCE(x.range_start,0) <= y.range_end
AND COALESCE(x.range_end,(SELECT MAX(range_end) FROM ranges)) >= y.range_start;
+----+-------------+-----------+----+-------------+-----------+
| id | range_start | range_end | id | range_start | range_end |
+----+-------------+-----------+----+-------------+-----------+
| 1 | NULL | NULL | 2 | 3 | 10 |
| 4 | NULL | 20 | 2 | 3 | 10 |
| 5 | 10 | 11 | 2 | 3 | 10 |
| 1 | NULL | NULL | 5 | 10 | 11 |
| 2 | 3 | 10 | 5 | 10 | 11 |
| 4 | NULL | 20 | 5 | 10 | 11 |
+----+-------------+-----------+----+-------------+-----------+
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