雪花中的 UNPIVOT 并添加其他列

Question

我正在尝试取消透视表 TABLE_A 并向查询中添加其他列

TABLE_A：

YEAR	ID	OCT	NOV	DEC	JAN	FEB	MAR	APR	MAY	JUN	JUL	AUG	SEP
2022	1	10	5	5	10	5	10	15	20	5	0	0	10

预期输出：

ID	MONTHLY_NO	MONTH	START_DATE	YEAR
1	10	10	10-01-2021	2021
1	5	11	11-01-2021	2021
1	5	12	12-01-2021	2021
1	10	1	01-01-2022	2022
1	5	2	02-01-2022	2022
1	10	3	03-01-2022	2022
1	15	4	04-01-2022	2022
1	20	5	05-01-2022	2022
1	5	6	06-01-2022	2022
1	0	7	07-01-2022	2022
1	0	8	08-01-2022	2022
1	10	9	09-01-2022	2022

我使用的查询：

SELECT ID, 
MONTHLY_NO, 
CASE 
WHEN TGT_MONTH='JAN' THEN 1
WHEN TGT_MONTH='FEB' THEN 2
WHEN TGT_MONTH='MAR' THEN 3
WHEN TGT_MONTH='APR' THEN 4
WHEN TGT_MONTH='MAY' THEN 5
WHEN TGT_MONTH='JUN' THEN 6
WHEN TGT_MONTH='JUL' THEN 7
WHEN TGT_MONTH='AUG' THEN 8
WHEN TGT_MONTH='SEP' THEN 9
WHEN TGT_MONTH='OCT' THEN 10
WHEN TGT_MONTH='NOV' THEN 11
WHEN TGT_MONTH='DEC' THEN 12
END AS MONTH
FROM TABLE_A
UNPIVOT( MONTHLY_NO FOR TGT_MONTH IN (JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC));

如何将 START_DATE 和 YEAR 列添加到查询中？可以请教吗？

Answer 1

按照UNPIVOT 文档中的模式，使用您的table_a

SELECT *
FROM table_a
UNPIVOT( monthly_no FOR tgt_month IN (jan, feb, mar, apr, may, jun, jul, aug, sep, oct, nov, dec))

应该给出（忽略缺少排序，并假设 year、id 和 monthly_no 都是 NUMBER）：

YEAR    ID  TGT_MONTH   MONTHLY_NO
2022    1   'JAN'       10
2022    1   'FEB'       5
2022    1   'MAR'       10
2022    1   'APR'       15
2022    1   'MAY'       20
2022    1   'JUN'       5
2022    1   'JUL'       0
2022    1   'AUG'       0
2022    1   'AUG'       10
2022    1   'OCT'       10
2022    1   'NOV'       5
2022    1   'DEC'       5

如果您不受列顺序的困扰，可以使用单个内联表单：

SELECT year, 
    id, 
    monthly_no, 
    TO_DATE(year::text || tgt_month, 'YYYYMON') AS start_date, 
    MONTH(start_date) AS month
FROM table_a
UNPIVOT( monthly_no FOR tgt_month IN (jan, feb, mar, apr, may, jun, jul, aug, sep, oct, nov, dec))

否则要按照您希望的顺序获取它，您必须重复执行相同的逻辑，或者嵌套它。

重复版本：

SELECT 
    id, 
    monthly_no, 
    MONTH(TO_DATE(year::text || tgt_month, 'YYYYMON')) AS month,
    TO_DATE(year::text || tgt_month, 'YYYYMON') AS start_date,
    year    
FROM table_a
UNPIVOT( monthly_no FOR tgt_month IN (jan, feb, mar, apr, may, jun, jul, aug, sep, oct, nov, dec))

嵌套：

SELECT 
    id, 
    monthly_no, 
    MONTH(start_date) AS month,
    start_date,
    year    
FROM (
    SELECT 
        id, 
        monthly_no, 
        TO_DATE(year::text || tgt_month, 'YYYYMON') AS start_date,
        year    
    FROM table_a
    UNPIVOT( monthly_no FOR tgt_month IN (jan, feb, mar, apr, may, jun, jul, aug, sep, oct, nov, dec))
)

哦，我只是故意摸摸你是 2021 年 10 月、11 月、12 月，即使你没有提到它。这可以通过一些内联 IFF 来解决

SELECT 
    id, 
    monthly_no, 
    MONTH(start_date) AS month,
    IFF(month >= 10, DATEADD('year', -1, start_date), start_date) AS start_date
    IFF(month >= 10, year -1, year) AS year 
FROM (
    SELECT 
        id, 
        monthly_no, 
        TO_DATE(year::text || tgt_month, 'YYYYMON') AS start_date,
        year    
    FROM table_a
    UNPIVOT( monthly_no FOR tgt_month IN (jan, feb, mar, apr, may, jun, jul, aug, sep, oct, nov, dec))
)

Answer 2

您应该能够只选择所需的其他列。我为此使用了一个 SQL 服务器示例，但原则上它应该以相同的方式工作。请参阅下面的查询：

SELECT ID, 
year,
CASE
WHEN TGT_MONTH='JAN' THEN '01/01/'+CAST(year as CHAR(4))
WHEN TGT_MONTH='FEB' THEN '02/01/'+CAST(year as CHAR(4))
WHEN TGT_MONTH='MAR' THEN '03/01/'+CAST(year as CHAR(4))
WHEN TGT_MONTH='APR' THEN '04/01/'+CAST(year as CHAR(4))
WHEN TGT_MONTH='MAY' THEN '05/01/'+CAST(year as CHAR(4))
WHEN TGT_MONTH='JUN' THEN '06/01/'+CAST(year as CHAR(4))
WHEN TGT_MONTH='JUL' THEN '07/01/'+CAST(year as CHAR(4))
WHEN TGT_MONTH='AUG' THEN '08/01/'+CAST(year as CHAR(4))
WHEN TGT_MONTH='SEP' THEN '09/01/'+CAST(year as CHAR(4))
WHEN TGT_MONTH='OCT' THEN '10/01/'+CAST(year as CHAR(4))
WHEN TGT_MONTH='NOV' THEN '11/01/'+CAST(year as CHAR(4))
WHEN TGT_MONTH='DEC' THEN '12/01/'+CAST(year as CHAR(4))
END as starting_date,
CASE 
WHEN TGT_MONTH='JAN' THEN 1
WHEN TGT_MONTH='FEB' THEN 2
WHEN TGT_MONTH='MAR' THEN 3
WHEN TGT_MONTH='APR' THEN 4
WHEN TGT_MONTH='MAY' THEN 5
WHEN TGT_MONTH='JUN' THEN 6
WHEN TGT_MONTH='JUL' THEN 7
WHEN TGT_MONTH='AUG' THEN 8
WHEN TGT_MONTH='SEP' THEN 9
WHEN TGT_MONTH='OCT' THEN 10
WHEN TGT_MONTH='NOV' THEN 11
WHEN TGT_MONTH='DEC' THEN 12
END AS MONTH
FROM 
  (
     SELECT year, id, oct, nov, dec, jan, feb, mar, apr, may, jun, jul, aug, sep
     FROM monthly_sales
  ) as pvt
  UNPIVOT(MONTHLY_NO FOR TGT_MONTH IN (JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV, DEC))
  As unpvt;

你可以在这里看到我的 sqlfiddle：http://sqlfiddle.com/#!18/48ee0/7/0