Tulis semula tajuk sebagai: Pengelompokan SQL lajur menggunakan nilai terbalik

Question

Andaikan saya mempunyai jadual seperti ini:

+---+---+---+---+---+
|G1 |G2 |G3 |G4 | V |
+---+---+---+---+---+
| A | B | C | D | 2 |
| E | F | G | H | 4 |
| C | D | A | B | 2 |
| E | F | G | H | 3 |
| E | I | G | L | 7 |
+---+---+---+---+---+

G1 dan G3 ialah jenis VARCHAR, G2 dan G4 ialah jenis INT

Jika saya melakukan GROUP BY yang mudah pada G1..G4, saya mendapat:

SELECT G1,G2,G3,G4,SUM(V) as V FROM Table GROUP BY G1, G2, G3, G4;

    +---+---+---+---+---+
    |G1 |G2 |G3 |G4 | V |
    +---+---+---+---+---+
    | A | B | C | D | 2 |
    | E | F | G | H | 7 |
    | C | D | A | B | 2 |
    | E | I | G | L | 7 |
    +---+---+---+---+---+

Saya ingin tahu sama ada boleh melakukan pengagregatan pada nilai terbalik G1, G2 <-> G3, G4. Hasil yang saya mahukan ialah:

+---+---+---+---+---+      +---+---+---+---+---+
|G1 |G2 |G3 |G4 | V |      |G1 |G2 |G3 |G4 | V |
+---+---+---+---+---+      +---+---+---+---+---+
| A | B | C | D | 4 |  或  | C | D | A | B | 4 |
| E | F | G | H | 7 |      | E | F | G | H | 7 |
| E | I | G | L | 7 |      | E | I | G | L | 7 |
+---+---+---+---+---+      +---+---+---+---+---+

Saya cuba mendapatkan baris terbalik tetapi saya masih tidak dapat mengagregatkannya kerana pendua. Pertanyaan ujian saya ialah:

SELECT DISTINCT *
FROM Table t1
JOIN Table t2 on t1.G1 = t2.G3 and t1.G2=t2.G4 and t1.G3=t2.G1 and t1.G4=t2.G2

    +---+---+---+---+---+---+---+---+---+---+
    |G1 |G2 |G3 |G4 | V |G1 |G2 |G3 |G4 | V |
    +---+---+---+---+---+---+---+---+---+---+
    | A | B | C | D | 2 | C | D | A | B | 2 |
    | C | D | A | B | 2 | A | B | C | D | 2 |
    +---+---+---+---+---+---+---+---+---+---+

Answer 1

Jika saya faham dengan betul, terbalikkan susunan lajur supaya A B C D sepadan dengan C D A B.

select 
         case when(g1 > g3) then g3 else g1 end G1,
         case when(g1 > g3) then g4 else g2 end G2,
         case when(g1 > g3) then g1 else g3 end G3,
         case when(g1 > g3) then g2 else g4 end G4, sum(V)
from tbl
group by case when(g1 > g3) then g3 else g1 end,
         case when(g1 > g3) then g4 else g2 end,
         case when(g1 > g3) then g1 else g3 end,
         case when(g1 > g3) then g2 else g4 end

db<>fiddle