Sql Oracle按组划分为基于日期的序列

我试图使用分区BY OVER来按某些列“分组”行。我对分区的使用有点了解，但是我想按日期“阻塞”分区。例如，如果我们有

|col1|col2       |
| A  |01/JAN/2012|
| A  |01/FEB/2012|
| B  |01/MAR/2012|
| B  |01/APR/2012|
| A  |01/MAY/2012|

我想用col1进行分区，但我想最后一个A与前两个“不同”，因为它是按日期用“B”行分隔的

如果我使用

它会屈服

但我真正想要的是

这是可能的使用分区超过？目前，我已经退回到使用游标来解析数据并分配组id，这样我就可以分离“a”的两个序列，但这相当慢

谢谢

---

标记。

通过几个分析，这是可能的：

select col1, col2, row_number() over (partition by grp order by col2) rnum
  from (select col1, col2, max(grp) over(order by col2) grp
          from (select col1, col2, 
                       case 
                         when lag(col1) over (order by col2) != col1
                         then
                           row_number() over (order by col2)
                         when row_number() over(order by col2) = 1 
                         then
                           1
                       end grp
                  from data));

i、 e:

首先获取col1按col2日期更改排序的边界：

然后我们可以填充这些空值：

SQL> select col1, col2, max(grp) over(order by col2) grp
  2    from (select col1, col2,
  3                  case
  4                    when lag(col1) over (order by col2) != col1
  5                    then
  6                      row_number() over (order by col2)
  7                    when row_number() over(order by col2) = 1
  8                    then
  9                      1
 10                  end grp
 11            from data);

C COL2             GRP
- --------- ----------
A 01-JAN-12          1
A 01-FEB-12          1
B 01-MAR-12          3
B 01-APR-12          3
A 01-MAY-12          5

然后是通过按col2排序并在grp上分区来分配行数的情况

---

fiddle:

首先，您应该找到每个记录的组ID，以便将所有相似的COL1排序到不同的组（如果它们之间有间隙）。然后在OVER语句中使用此GROUP_ID和COL1：

---

请看下面我的方法，这与Dazzal的答案相似，逻辑稍有不同：

步骤1：

--find the swhitches to new groups
select col1, col2, 
    case when nvl(lag(col1) over (order by col2),sysdate) <> col1 then 1 end as new_grp
  from data;

COL1    COL2        NEW_GRP
A   January, 01 2012    1
A   February, 01 2012   (null)
B   March, 01 2012      1
B   April, 01 2012      (null)
A   May, 01 2012        1

步骤2：

--identify/mark the groups

select col1, col2, sum(new_grp) over (order by col2) as grp
from(
  select col1, col2, 
    case when nvl(lag(col1) over (order by col2),sysdate) <> col1 then 1 end as new_grp
  from data)
  ;

COL1    COL2        NEW_GRP
A   January, 01 2012    1
A   February, 01 2012   1
B   March, 01 2012      2
B   April, 01 2012      2
A   May, 01 2012        3

步骤3：

--find the row_number within group
select col1, col2, row_number() over(partition by grp order by col2) rn
from(
  select col1, col2, sum(new_grp) over (order by col2) as grp
  from(
    select col1, col2, 
      case when nvl(lag(col1) over (order by col2),sysdate) <> col1 then 1 end as new_grp
    from data
      )
  );

COL1    COL2        NEW_GRP
A   January, 01 2012    1
A   February, 01 2012   2
B   March, 01 2012      1
B   April, 01 2012      2
A   May, 01 2012        1

---

您不需要分区。您需要将日期转换为DD/MM/YYYY格式并进行排序。或者，如果你必须的话，你可以用MM部分划分，这会给你01,02,03。。。并且可以根据需要进行分区并轻松转换为数字。但你不需要所有这些。。。不要使你的问题复杂化。始终保持简单。外部查询仅用于将日期重新格式化为DD/MON/YYYY格式：

SELECT val, to_char(to_date(dt, 'DD/MM/YYYY'), 'DD/MON/YYYY') formatted_date 
  FROM
( -- Format your date to DD/MM/YYYY and order by it --
SELECT 'A' val, to_char(to_date('01/JAN/2012'), 'DD/MM/YYYY') dt FROM dual  
 UNION
SELECT 'A', to_char(to_date('01/FEB/2012'), 'DD/MM/YYYY') FROM dual  
 UNION
SELECT 'B',to_char(to_date('01/MAR/2012'), 'DD/MM/YYYY') FROM dual  
 UNION
SELECT 'B',to_char(to_date('01/APR/2012'), 'DD/MM/YYYY') FROM dual  
 UNION
SELECT 'A',to_char(to_date('01/MAY/2012'), 'DD/MM/YYYY') FROM dual  
ORDER BY 2
)
/

您的日期按照您的要求进行排序，然后：

VAL FORMATTED_DATE
-------------------
A   01/JAN/2012
A   01/FEB/2012
B   01/MAR/2012
B   01/APR/2012
A   01/MAY/2012

---

谢谢这个@valex这就是我想要的。其他解决方案也有效，但这是最简洁的

--find the swhitches to new groups
select col1, col2, 
    case when nvl(lag(col1) over (order by col2),sysdate) <> col1 then 1 end as new_grp
  from data;

COL1    COL2        NEW_GRP
A   January, 01 2012    1
A   February, 01 2012   (null)
B   March, 01 2012      1
B   April, 01 2012      (null)
A   May, 01 2012        1

--identify/mark the groups

select col1, col2, sum(new_grp) over (order by col2) as grp
from(
  select col1, col2, 
    case when nvl(lag(col1) over (order by col2),sysdate) <> col1 then 1 end as new_grp
  from data)
  ;

COL1    COL2        NEW_GRP
A   January, 01 2012    1
A   February, 01 2012   1
B   March, 01 2012      2
B   April, 01 2012      2
A   May, 01 2012        3

--find the row_number within group
select col1, col2, row_number() over(partition by grp order by col2) rn
from(
  select col1, col2, sum(new_grp) over (order by col2) as grp
  from(
    select col1, col2, 
      case when nvl(lag(col1) over (order by col2),sysdate) <> col1 then 1 end as new_grp
    from data
      )
  );

COL1    COL2        NEW_GRP
A   January, 01 2012    1
A   February, 01 2012   2
B   March, 01 2012      1
B   April, 01 2012      2
A   May, 01 2012        1

SELECT val, to_char(to_date(dt, 'DD/MM/YYYY'), 'DD/MON/YYYY') formatted_date 
  FROM
( -- Format your date to DD/MM/YYYY and order by it --
SELECT 'A' val, to_char(to_date('01/JAN/2012'), 'DD/MM/YYYY') dt FROM dual  
 UNION
SELECT 'A', to_char(to_date('01/FEB/2012'), 'DD/MM/YYYY') FROM dual  
 UNION
SELECT 'B',to_char(to_date('01/MAR/2012'), 'DD/MM/YYYY') FROM dual  
 UNION
SELECT 'B',to_char(to_date('01/APR/2012'), 'DD/MM/YYYY') FROM dual  
 UNION
SELECT 'A',to_char(to_date('01/MAY/2012'), 'DD/MM/YYYY') FROM dual  
ORDER BY 2
)
/

VAL FORMATTED_DATE
-------------------
A   01/JAN/2012
A   01/FEB/2012
B   01/MAR/2012
B   01/APR/2012
A   01/MAY/2012