[SQL]UNPIVOT 多個欄位

有朋友問「如何直接unpivot成2個欄位」，如下所示，

 

先準備測試資料如下，

01 create table T (
02 no varchar(10),
03 yearx varchar(4),
04 z_type varchar(1),
05 A01 smallint,
06 B01 smallint,
07 A02 smallint,
08 B02 smallint,
09 A03 smallint,
10 B03 smallint
11 )
12 go
13
14 insert into T VALUES('Z01','2012','1',100,-10,200,30,50,60);
15 insert into T VALUES('Z01','2012','3',200,20,100,20,30,40);
16 insert into T VALUES('Z01','2013','3',300,30,10,50,70,30);
17
18 SELECT * FROM T;

 

因為原本欄位A01, A02, A03要放到欄位A，B01, B02, B03要放到欄位B，所以需要2個UNPIVOT，如下，

1 SELECT no, yearx, z_type, A, B, x1, x2
2 FROM
3    (SELECT *
4    FROM T) p
5 UNPIVOT ( A FOR x1 IN (A01, A02, A03) )AS UnA
6 UNPIVOT ( B FOR x2 IN (B01, B02, B03) )AS UnB

 

上面的輸出筆數為27筆，而我們可以發現，x1, x2欄位中，A01 搭配 B01，A02 要搭配 B02，A03 要搭配 B03，如下圖所示，

 

所以我們需要再加入 關鍵的 WHERE 條件， RIGHT(x1, 1) = RIGHT(x2, 1)，就可以過濾出我們所需要的資料，如下，

1 SELECT no, yearx, z_type, A, B, x1, x2
2 FROM
3    (SELECT *
4    FROM T) p
5 UNPIVOT ( A FOR x1 IN (A01, A02, A03) )AS UnA
6 UNPIVOT ( B FOR x2 IN (B01, B02, B03) )AS UnB
7 WHERE RIGHT(x1, 1) = RIGHT(x2, 1)

 

如果要加上序號的話，就加入 ROW_NUMBER 就可以了，如下，

01 SELECT *
02 , ROW_NUMBER() OVER(PARTITION BY no, yearx, z_type ORDER BY  no, yearx, z_type) AS SEQX
03 FROM
04 (
05 SELECT no, yearx, z_type, A, B, x1, x2
06 FROM
07    (SELECT *
08    FROM T) p
09 UNPIVOT ( A FOR x1 IN (A01, A02, A03) )AS UnA
10 UNPIVOT ( B FOR x2 IN (B01, B02, B03) )AS UnB
11 WHERE RIGHT(x1, 1) = RIGHT(x2, 1)
12 ) T2