如何選擇3列和GROUP作爲一個沒有重複的條目在MySQL中？

Question

我有3列與遊戲類型名字......是這樣的：

 
+-------------+-------------+----------+ 
| genre1  | genre2  | genre3 | 
+-------------+-------------+----------+ 
| Action  | Shooter |   | 
| Action  |    |   | 
| Sport  |    |   | 
| Adventure |    |   | 
| Action  | Adventure | Strategy | 

我的問題是，如何讓輸出一列的所有名稱無重複，如：

 
Action 
Shooter 
Sport 
Adventure 
Strategy 

Answer 1

UNION運營商將消除重複。

SELECT genre1 AS genre FROM YourTable 
UNION 
SELECT genre2 AS genre FROM YourTable 
UNION 
SELECT genre3 AS genre FROM YourTable