从SQL中的一个左属性获取多个属性

Question

如果我有这样的桌子

UserName | BoardName
-----------------------
Alice   Research
Ethan   Research
Ethan   Gardening
Ethan   Movies
Jack    Travel
Jack    Movies
Tom         Gardening
Tom         Teaching
Tom         Travel
Tom         Movies
Tom         Study

我可以使用PL/SQL查询获得这样的结果吗？

Alice   Research
Ethan   Research
            Gardening
            Movies
Jack    Travel
            Movies
Tom         Gardening
            Teaching
            Travel
            Movies
            Study

注意到在UserNames之后是如何出现空白单元格的？如果问题不太清楚，很抱歉。

我认为一个由查询组成的组可以工作，但我不确定。

Answer 1

请尝试：

SELECT  
     case when UserName=lag(UserName) OVER (ORDER BY UserName) 
     then null 
     else UserName end UserName,
     UserEmail, 
     BoardName
FROM 
     YourTable;

SQL Fiddle演示

Answer 2

SELECT
    UserName,
    BoardName
FROM
    TheTable
GROUP BY 
    UserName,
    BoardName

会让你

John    Cooking
John    Travel
Tom     Cooking
Bill    Sport

因此，诀窍是找出组中的行num并处理它。

也许是这样的？

SELECT
    CASE
       WHEN ROW_NUMBER() OVER (partition by GROUP order by UserName,  BoardName) > 1 THEN ''
       ELSE UserName
    END AS UserName,   
    BoardName
FROM
    TheTable
GROUP BY 
    CASE
       WHEN ROW_NUMBER() OVER (partition by GROUP order by UserName,  BoardName) > 1 THEN ''
       ELSE UserName
    END,   
    BoardName

我没有神谕所以不能测试它。