mysql查询的重复结果

执行查询后，在尝试获取树结构的类别id时，我们将获得重复的id。 我们期待一个没有重复id的输出

SELECT 
  GROUP_CONCAT(CONCAT_WS(',',t1.CategoryID,t2.CategoryID,t3.`CategoryID`, t4.CategoryID)) AS id 
FROM prodcategory AS t1 
LEFT JOIN prodcategory AS t2 ON t2.ParentCategoryID = t1.CategoryID 
LEFT JOIN prodcategory AS t3 ON t3.ParentCategoryID = t2.CategoryID 
LEFT JOIN prodcategory AS t4 ON t4.ParentCategoryID=t3.CategoryID 
WHERE t1.ParentCategoryID =41

实际产量：

190,256,190,257,191,261,300,191,262,192,267

190,256,257,191,261,300,262,192,267

预期产出：

190,256,190,257,191,261,300,191,262,192,267

190,256,257,191,261,300,262,192,267

示例数据库数据：

CategoryID |  CategoryName |  ParentCategoryID
   41      |       a       |        1
   190     |       b       |        41
   191     |       c       |        41
   192     |       d       |        41
   256     |       e       |        190
   257     |       f       |        190
   261     |       g       |        191
   262     |       h       |        191
   300     |       i       |        261
   267     |       j       |        192 

---

对于重复的结果，可以使用不同的关键字

    SELECT GROUP_CONCAT(CONCAT_WS(',',DISTINCT 
    t1.CategoryID,DISTINCT t2.CategoryID,DISTINCT t3.`CategoryID`,DISTINCT  
    t4.CategoryID)) AS id FROM prodcategory AS t1 
    LEFT JOIN prodcategory AS t2 ON t2.ParentCategoryID = t1.CategoryID 
    LEFT JOIN prodcategory AS t3 ON t3.ParentCategoryID = t2.CategoryID 
    LEFT JOIN prodcategory AS t4 ON t4.ParentCategoryID=t3.CategoryID 
    WHERE t1.ParentCategoryID =41

---

附加与您正在生成的输出相匹配的样本数据。

选择GROUP_CONCAT（不同的CONCAT_WS（..

有帮助吗？@Arulkumar仍然存在重复项。@KamilGosciminski您需要带数据的示例表结构？@SüreshAK是的，请阅读有关提供MVCE的更多信息：结果中仍然存在重复项使用数据发送给我您的数据库转储？？dhanushkasasankapayza@gmail.comadding引发语法错误的每列中都不相同