你应该试试 GROUP BY 相反，像这样：

SELECT studentName, MIN(joiningDate)
FROM student
GROUP BY studentName

下面是bigquery标准sql，适用于该表中任意数量的附加字段，不更改查询

# standardSQL

SELECT AS VALUE ARRAY_AGG(t ORDER BY joiningDate DESC LIMIT 1)[OFFSET(0)]
FROM `project.dataset.student` t
GROUP BY studentName

您可以使用问题中的虚拟数据测试、玩上面的游戏：

# standardSQL

WITH `project.dataset.student` AS (
  SELECT 'Rosy'studentName, '2018-06-25' joiningDate UNION ALL
  SELECT 'Meera', '2018-07-20' UNION ALL                  
  SELECT 'Rosy', '2018-06-20' 
) 
SELECT AS VALUE ARRAY_AGG(t ORDER BY joiningDate LIMIT 1)[OFFSET(0)]
FROM `project.dataset.student` t
GROUP BY studentName

有结果的

Row studentName joiningDate  
1   Rosy        2018-06-25   
2   Meera       2018-07-20

你可以用 Group By 与 Max() 聚合函数（获取最近加入的日期）。请尝试以下查询：

SELECT studentName, 
       MAX(joiningDate) AS joiningDate
FROM student 
GROUP BY studentName
ORDER BY joiningDate ASC