只讀取唯一結果從SQL數據庫

Question

數據庫表

ID  Post    Tags 
    1  Range rover   range-rover,cars 
    2  Lamborghini   lamborghini,cars 
    3  Kawasaki   kawasaki,bikes 
    4  Yamaha R1   yamaha,r1,bikes 

我想從結果SQL刪除重複值

我得到什麼，當我取回從數據庫標籤（標籤中）

SELECT Tags from posts; 

Resut：

​​

我需要的不是再次顯示相同的結果。

range-rover,cars lamborghini kawasaki,bikes yamaha,r1 

Answer 1

可以使用符合表和SUBSTRING_INDEX分割你的文字：

SELECT DISTINCT SUBSTRING_INDEX(SUBSTRING_INDEX(t.tags, ',', n.n), ',', -1) AS val 
FROM posts t 
CROSS JOIN 
(
    SELECT a.N + b.N * 10 + 1 n 
    FROM 
    (SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) a 
    ,(SELECT 0 AS N UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) b 
) n 
WHERE n.n <= 1 + (LENGTH(t.tags) - LENGTH(REPLACE(t.tags, ',', ''))) 

SqlFiddleDemo

如果你需要一個行添加GROUP_CONCAT：

SELECT GROUP_CONCAT(DISTINCT SUBSTRING_INDEX(SUBSTRING_INDEX(t.tags, ',', n.n), ',', -1)) AS val 
... 

SqlFiddleDemo2