MySQL 获取无限级某级的全路径

传递参数：文件夹ID

 DROP FUNCTION IF EXISTS RecursionFolderFullPath;

 CREATE FUNCTION RecursionFolderFullPath(folderId INT())
 RETURNS VARCHAR()
 BEGIN
 declare fullPath VARCHAR() default '';
 declare parentId INT() default '';

 select concat(folder_name,'/',fullPath),folder_parent_id into fullPath,parentId
 from folder
 where folder_id=folderId;

 WHILE parentId >  DO
 select concat(folder_name,'/',fullPath),folder_parent_id into fullPath,parentId
 from folder
 where folder_id=parentId;
 END WHILE;

 return fullPath;
 END;

调用：

select RecursionFolderFullPath();

结果：