Question

也许我错过了一些逻辑或一种轻松做到这一点的方法。

有一张带有颜色的表格，有些可能有0,1,2,3或更多颜色与同一colorHue

内的其他颜色相匹配

id  colorName   colorHue    ColorNumber
----------------------------------------------------
1   Orange      Og          1000
2   Pumpkin     Og          1000
3   Red         Rd          1001
4   Brick       Rd          1001
5   Carrot      Og          1000
6   Blue        Blue        1002
7   Scarlet     Rd          1001

我需要列出所有颜色的VIEW和其他可能的颜色，而不显示当前行的颜色名称。

id  colorName   Other Colors
----------------------------------------------------
1   Orange      Pumpkin,Carrot
2   Pumpkin     Orange,Carrot
3   Red         Brick,Scarlet
4   Brick       Red,Scarlet
5   Carrot      Orange,Pumpkin
6   Blue        
7   Scarlet     Red,Brick

我可以很容易地获得所有这些GROUP_CONCAT，但无法弄清楚如何消除对当前行的自引用。所以我明白了：

id  colorName   Other Colors
----------------------------------------------------
1   Orange      Orange,Pumpkin,Carrot
2   Pumpkin     Orange,Pumpkin,Carrot
3   Red         Red,Brick,Scarlet
4   Brick       Red,Brick,Scarlet
5   Carrot      Orange,Pumpkin,Carrot
6   Blue        Blue
7   Scarlet     Red,Brick,Scarlet

Answer 1

http://sqlfiddle.com/#!9/43c122/2

SELECT colorHue, 
      GROUP_CONCAT(IF(colorHue=colorName,null,colorName))
FROM colors
GROUP BY colorHue

更新 http://sqlfiddle.com/#!9/43c122/8

SELECT c.*, 
      GROUP_CONCAT(c1.colorName)
FROM colors c
LEFT JOIN colors c1
ON c.colorHue = c1.colorHue
   AND c.id != c1.id
GROUP BY c.id

GROUP_CONCAT具有自我排除功能

1 个答案: