如何在不聚合的情况下将 Teradata 表从长格式重塑为宽格式？

Question

虽然在回答有关将长表转换为宽格式的各种问题时提供了使用 Teradata 的 PIVOT 函数，但这些建议涉及使用聚合函数，即 PIVOT 的一个参数。
有没有办法在不聚合的情况下重塑/旋转数据？

这样的表可以吗...

Initial	Name
A	Abel
A	Adriana
A	Alberto
B	Billy
B	Bob
C	Carla
C	Carlos
C	Cesar
C	Cristina

...变成下面？

Initial	Name1	Name2	Name3	Name4
A	Abel	Adriana	Alberto
B	Billy	Bob
C	Carla	Carlos	Cesar	Cristina

这是我用于在 Teradata 16.20 中创建第一个表的代码：

CREATE VOLATILE TABLE MyTab (Initial varchar(1), "Name" varchar(10))
UNIQUE PRIMARY INDEX(Initial, "Name") ON COMMIT PRESERVE ROWS;

INSERT INTO MyTab values ('A','Abel');
INSERT INTO MyTab values ('A','Adriana');
INSERT INTO MyTab values ('A','Alberto');
INSERT INTO MyTab values ('B','Billy');
INSERT INTO MyTab values ('B','Bob');
INSERT INTO MyTab values ('C','Carla');
INSERT INTO MyTab values ('C','Carlos');
INSERT INTO MyTab values ('C','Cesar');
INSERT INTO MyTab values ('C','Cristina');

SELECT * FROM MyTab ORDER BY Initial, "Name";

Answer 1

如果知道列数，可以使用条件聚合：

select initial,
       max(case when seqnum = 1 then name end) as name1,
       max(case when seqnum = 2 then name end) as name2,
       max(case when seqnum = 3 then name end) as name3,
       max(case when seqnum = 4 then name end) as name4
from (select t.*,
             row_number() over (partition by initial order by name) as seqnum
      from mytab t
     ) t
group by initial;