问题
I have the following problem:
Given the following table test in an oracle sql database:
+----+------+-------+------+
| id | name | start | stop |
+----+------+-------+------+
| 1 | A | 1 | 5 |
+----+------+-------+------+
| 2 | A | 2 | 6 |
+----+------+-------+------+
| 3 | A | 5 | 8 |
+----+------+-------+------+
| 4 | A | 9 | 10 |
+----+------+-------+------+
| 5 | B | 3 | 6 |
+----+------+-------+------+
| 6 | B | 4 | 8 |
+----+------+-------+------+
| 7 | B | 1 | 2 |
+----+------+-------+------+
I would like to find the number of overlapping intervals (endpoints included) [start, stop] n_overlap, for all id having the same name, i.e.:
+----+------+-------+------+-----------+
| id | name | start | stop | n_overlap |
+----+------+-------+------+-----------+
| 1 | A | 1 | 5 | 3 |
+----+------+-------+------+-----------+
| 2 | A | 2 | 6 | 3 |
+----+------+-------+------+-----------+
| 3 | A | 4 | 8 | 3 |
+----+------+-------+------+-----------+
| 4 | A | 9 | 10 | 1 |
+----+------+-------+------+-----------+
| 5 | B | 3 | 6 | 2 |
+----+------+-------+------+-----------+
| 6 | B | 4 | 8 | 2 |
+----+------+-------+------+-----------+
| 7 | B | 1 | 2 | 1 |
+----+------+-------+------+-----------+
回答1:
One method uses a correlated subquery:
select t.*,
(select count(*)
from test t2
where t2.name = t.name and
t2.start < t.end and
t2.end > t.start
) as num_overlaps
from test t;
来源：https://stackoverflow.com/questions/52484909/sql-oracle-counting-number-of-overlapping-intervals