Question

为了填充缺失值，我需要对那些缺失值进行插值。

我已经获得了如下数据集（示例）：

mypy

因此，我很期待：

Country    Year    Value
A          2000    1.5
A          2001    2.5
A          2002    null
A          2003    4.5
B          2000    null
B          2000    null    
B          2002    5.3
B          2003    6.3
C          2000    1
C          2001    null
C          2002    null
C          2003    4

如何通过线性插值来插值此值。我真的不知道如何在oracle中有效地做到这一点。

Answer 1

Oracle具有用于线性插值的各种功能。 REGR_SLOPE和REGR_INTERCEPT在这里很有帮助。

您遇到的问题是，它不是价值和年份之间的线性回归。它是国家组中值和行号之间的线性回归。因此，在计算插值之前，需要先计算该行号。

with input_data (country, year, value) AS (
  SELECT 'A',          2000,    1.5  FROM DUAL UNION ALL
  SELECT 'A',          2001,    2.5  FROM DUAL UNION ALL
  SELECT 'A',          2002,    null FROM DUAL UNION ALL
  SELECT 'A',          2003,    4.5  FROM DUAL UNION ALL
  SELECT 'B',          2000,    null FROM DUAL UNION ALL
  SELECT 'B',          2000,    null FROM DUAL UNION ALL
  SELECT 'B',          2002,    5.3  FROM DUAL UNION ALL
  SELECT 'B',          2003,    6.3  FROM DUAL UNION ALL
  SELECT 'C',          2000,    1    FROM DUAL UNION ALL
  SELECT 'C',          2001,    null FROM DUAL UNION ALL
  SELECT 'C',          2002,    null FROM DUAL UNION ALL
  SELECT 'C',          2003,    4    FROM DUAL
), ordered_input as (   
  SELECT
    i.*,
    row_number() over ( partition by country order by year) rn
  FROM input_data i
)
SELECT 
  country,
  year,
  value, 
  rn * regr_slope(value, rn) over ( partition by country) +
       regr_intercept(value, rn) over ( partition by country)
    as interpolated_value
FROM ordered_input
ORDER BY country, year, rn;

+---------+------+-------+--------------------+
| COUNTRY | YEAR | VALUE | INTERPOLATED_VALUE |
+---------+------+-------+--------------------+
| A       | 2000 |   1.5 |                1.5 |
| A       | 2001 |   2.5 |                2.5 |
| A       | 2002 |       |                3.5 |
| A       | 2003 |   4.5 |                4.5 |
| B       | 2000 |       |                3.3 |
| B       | 2000 |       |                4.3 |
| B       | 2002 |   5.3 |                5.3 |
| B       | 2003 |   6.3 |                6.3 |
| C       | 2000 |     1 |                  1 |
| C       | 2001 |       |                  2 |
| C       | 2002 |       |                  3 |
| C       | 2003 |     4 |                  4 |
+---------+------+-------+--------------------+

Oracle中的线性插值（特殊情况）

1 个答案: