在 oracle 中用 Unpivot 替换 union all

Question

我有以下查询：

SELECT COL1,ABC AS COL2,'1' AS SEQ,'GRP 10' AS GRP_NAME,'ABC' AS INPUT_COL_NAME,'NEW1' AS OUTPUT_COL_NAME FROM TABLE1
UNION ALL
SELECT COL1,MNO AS COL2,'2' AS SEQ,'GRP 10' AS GRP_NAME,'MNO' AS INPUT_COL_NAME,'NEW2' AS OUTPUT_COL_NAME FROM TABLE1
UNION ALL
SELECT COL1,XYZ AS COL2,'3' AS SEQ,'GRP 10' AS GRP_NAME,'XYZ' AS INPUT_COL_NAME,'NEW3' AS OUTPUT_COL_NAME FROM TABLE1

输入TABLE数据：

SELECT COL1,COL2 FROM TABLE1

COL1 ABC MNO XYZ

1 0 20 100

2 15 50 150

输出是：

COL1 COL2 SEQ GRP_NAME INPUT_COL_NAME OUTPUT_COL_NAME

1 0 1 GRP_NEW ABC NEW1

2 15 1 GRP_NEW ABC NEW1

1 20 2 GRP_NEW MNO NEW2

2 50 2 GRP_NEW MNO NEW2

1 100 3 GRP_NEW XYZ NEW3

2 150 3 GRP_NEW XYZ NEW3

上面的查询可以转化为PIVOT查询吗？生成相同的输出。

Answer 1

你想要UNPIVOT（而不是PIVOT）：

SELECT col1,
       col2,
       seq,
       'GRP_NEW' AS grp_name,
       input_col_name,
       output_col_name
FROM   table1
UNPIVOT (
  input_col_name FOR ( col2, seq, output_col_name ) IN (
    abc AS ( 'ABC', 1, 'NEW1' ),
    mno AS ( 'MNO', 2, 'NEW2' ),
    xyz AS ( 'XYZ', 3, 'NEW3' )
  )
)
ORDER BY seq, col1

其中，对于示例数据：

CREATE TABLE table1 ( COL1, ABC, MNO, XYZ ) AS
SELECT 1,  0, 20, 100 FROM DUAL UNION ALL
SELECT 2, 15, 50, 150 FROM DUAL

输出：

COL1 COL2 SEQ GRP_NAME INPUT_COL_NAME OUTPUT_COL_NAME

1 ABC 1 GRP_NEW 0 NEW1

2 ABC 1 GRP_NEW 15 NEW1

1 MNO 2 GRP_NEW 20 NEW2

2 MNO 2 GRP_NEW 50 NEW2

1 XYZ 3 GRP_NEW 100 NEW3

2 XYZ 3 GRP_NEW 150 NEW3

db<>fiddle here

在 oracle 中用 Unpivot 替换 union all

Replacing union all with Unpivot in oracle

sql

oracle

union

unpivot

COL1	COL2	SEQ	GRP_NAME	INPUT_COL_NAME	OUTPUT_COL_NAME
1	0	1	GRP_NEW	ABC	NEW1
2	15	1	GRP_NEW	ABC	NEW1
1	20	2	GRP_NEW	MNO	NEW2
2	50	2	GRP_NEW	MNO	NEW2
1	100	3	GRP_NEW	XYZ	NEW3
2	150	3	GRP_NEW	XYZ	NEW3