Question

如果我有这样的表

Number Status
------ ------
1      A
2      A
3      A
4      U
5      U
6      A
7      U
8      U
9      A
10     A

我可以使用什么查询将范围分组到Status = A？

的范围内

Range  Count  Status
-----  -----  ------
1-3    3      A
6-6    1      A
9-10   2      A

我的查询是

select min(number) || '--' || max(number), count(*), Status
from table
where Status = 'A'
group by Status

Range  Count  Status
-----  -----  ------
1-10   6      A

Answer 1

SQL Fiddle

Oracle 11g R2架构设置：

create table x(
  num_ number,
  status_ varchar2(1)
  );

insert into x values(1,'A');
insert into x values(2,'A');
insert into x values(3,'A');
insert into x values(4,'U');
insert into x values(5,'U');
insert into x values(6,'A');
insert into x values(7,'U');
insert into x values(8,'U');
insert into x values(9,'A');
insert into x values(10,'A');

查询1 ：

select min(num_) || '-'  || max(num_) range_, status_,
count(1) count_
from
(
  select num_, status_,
  num_ - row_number() over (order by status_, num_) y --gives a group number to each groups, which have same status over consecutive records.
  from x
 )
 where status_ = 'A'
 group by y, status_
 order by range_

<强> Results ：

| RANGE_ | STATUS_ | COUNT_ |
|--------|---------|--------|
|    1-3 |       A |      3 |
|    6-6 |       A |      1 |
|   9-10 |       A |      2 |

Answer 2

这是一个很好的方式，由Aketi Jyuuzou给出的名字“Tabibitosan method”。

SQL> WITH data AS
  2    (SELECT num - DENSE_RANK() OVER(PARTITION BY status ORDER BY num) grp,
  3      status,
  4      num
  5    FROM t
  6    )
  7  SELECT MIN(num)
  8    ||' - '
  9    || MAX(num) range,
 10    COUNT(*) cnt
 11  FROM data
 12  WHERE status='A'
 13  GROUP BY grp
 14  ORDER BY grp
 15  /

RANGE         CNT
------ ----------
1 - 3           3
6 - 6           1
9 - 10          2

SQL>

注意最好使用DENSE_RANK来避免重复。

表格

SQL> SELECT * FROM t ORDER BY num; NUM S ---------- - 1 A 1 A 2 A 2 A 3 A 4 U 5 U 6 A 7 U 8 U 9 A NUM S ---------- - 10 A 12 rows selected.

num = 1有重复数据。

使用 DENSE_RANK ：

SQL> WITH data AS 2 (SELECT num - DENSE_RANK() OVER(PARTITION BY status ORDER BY num) grp, 3 status, 4 num 5 FROM t 6 ) 7 SELECT MIN(num) 8 ||' - ' 9 || MAX(num) range, 10 COUNT(*) cnt 11 FROM data 12 WHERE status='A' 13 GROUP BY grp 14 ORDER BY grp 15 / RANGE CNT ------ ---------- 1 - 3 5 6 - 6 1 9 - 10 2 SQL>

使用 ROW_NUMBER ：

SQL> WITH DATA AS 2 (SELECT num - ROW_NUMBER() OVER(PARTITION BY status ORDER BY num) grp, 3 status, 4 num 5 FROM t 6 ) 7 SELECT MIN(num) 8 ||' - ' 9 || MAX(num) range, 10 COUNT(*) cnt 11 FROM data 12 WHERE status='A' 13 GROUP BY grp 14 ORDER BY grp 15 / RANGE CNT ------ ---------- 2 - 3 2 1 - 2 2 1 - 6 2 9 - 10 2 SQL>

因此，如果出现重复项， ROW_NUMBER 查询会产生错误的结果。您应该使用 DENSE_RANK 。

如何在oracle中选择记录范围内的范围

2 个答案: