我不能找出如何检查数据库侧,如果两个范围,即可以处理空值(例如范围A:空 - 空范围B:3 - 10),重叠。
在这种情况下,这两个范围的重叠,因为在我的代码空 - 空它等于-∞和+∞所以3 - 10里面-∞ - +∞。
问题是,我需要建立一个由具有与我试图创建stock_rule记录重叠的范围我的表stock_rule返回所有记录的查询。
如果计数大于零重大的话,我无法保存记录。
我试图实现,以这种方式使用COALESCE函数(MySQL的8.0):
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)
我想这样的事情会工作...
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 |
+----+-------------+-----------+----+-------------+-----------+
mysql>