将用户行转换为动态列数

Question

我有一个table喜欢

_________________________
|    ACCOUNT      REP    |
|________________________|
|    Tradewind    Bob    |
|------------------------|
|    Tradewind    Joe    |
|------------------------|
|    Tradewind    Rick   |
|------------------------|
|    Headlands    Joe    |
|------------------------|
|    Headlands    Bob    |
|________________________|

我想把它变成

  _________________________________________
  |  ACCOUNT     REP1      REP2     REP3  |
  |_______________________________________| 
  |  Tradewind   Bob       Joe      Rick  |
  |---------------------------------------|
  |  Headlands   Bob       Joe      NULL  |
  |_______________________________________|

我试图弄清楚这一点并理解它是对 PIVOT 关键字的某种使用。也许以某种方式使用 SELECT OVER ？

Answer 1

您可能会使用：

select account,
       max(case when rep='Bob' then 'Bob' end) as Rep1,
       max(case when rep='Joe' then 'Joe' end) as Rep2,
       max(case when rep='Rick' then 'Rick' end) as Rep3
  from tab
 group by account
 order by account desc;

Rextester Demo

Answer 2

如果你想要三列，那么你可以使用条件聚合：

select account,
       max(case when seqnum = 1 then rep end) as Rep1,
       max(case when seqnum = 2 then rep end) as Rep2,
       max(case when seqnum = 3 then rep end) as Rep3
from (select t.*, row_number() over (partition by account order by rep) as seqnum
      from t
     ) t
group by account;

将用户行转换为动态列数

Convert rows of users to dynamic number of columns

sql

pivot

crosstab