在查询执行后,当我们尝试获取树状类别ID时,我们得到了重复的ID。我们希望输出不包含重复ID。
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
实际输出:
190,256,190,257,191,261,300,191,262,192,267
预期输出:
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
SELECT GROUP_CONCAT(DISTINCT CONCAT_WS(..
有帮助吗? - Arulkumar