MySQL的GROUP_CONCAT上加入行DISTINCT

Question

我有一个查询谁是这样的

SELECT 
producttemp.*, 
GROUP_CONCAT(colors.id) as color, 
GROUP_CONCAT(DISTINCT upc.UPC) as upc 
FROM producttemp 
INNER JOIN productcolor 
ON productcolor.productid=producttemp.id 
INNER JOIN upc 
ON upc.productid=producttemp.id 
INNER JOIN colors 
ON colors.id=productcolor.colorid 
INNER JOIN categorie 
ON categorie.id = producttemp.productcategorie 
GROUP BY producttemp.id 
LIMIT 5 

出于某种原因或antoher我在resultfield得到“色”重复的值，即“1,2,1,2”。为什么DISTINCT无法在连接的行上工作？有没有机会解决或者我错过了一个观点？

Answer 1

尝试DISTINCT上colors.id ::

SELECT 
producttemp.*, 
GROUP_CONCAT(DISTINCT colors.id) as color, 
GROUP_CONCAT(DISTINCT upc.UPC) as upc 
FROM producttemp 
INNER JOIN productcolor 
ON productcolor.productid=producttemp.id 
INNER JOIN upc 
ON upc.productid=producttemp.id 
INNER JOIN colors 
ON colors.id=productcolor.colorid 
INNER JOIN categorie 
ON categorie.id = producttemp.productcategorie 
GROUP BY producttemp.id 
LIMIT 5