转向Oracle 10g

Question

我正在使用oracle 10g.我有临时表TEMP.

TEMP具有以下结构: -

USER COUNT TYPE
---- ----- ----
   1    10   T1
   2    21   T2
   3    45   T1
   1     7   T1
   2     1   T3

我需要一个查询,它将显示所有类型都有列名,类型可以有任何值T1, T2,..Tn,结果将如下: -

USER T1 T2 T3
---- -- -- --
   1 17  0  0
   2  0 21  1
   3 45  0  0

和用户列将显示所有用户,T1, T2列将显示类型的总数.

Answer 1

在Oracle 10g中,没有任何PIVOT功能,但您可以使用带有以下内容的聚合来复制它CASE:

select usr,
  sum(case when tp ='T1' then cnt else 0 end) T1,
  sum(case when tp ='T2' then cnt else 0 end) T2,
  sum(case when tp ='T3' then cnt else 0 end) T3
from temp
group by usr;

请参阅SQL Fiddle with Demo

如果你有Oracle 11g +那么你可以使用这个PIVOT功能:

select *
from temp
pivot
(
  sum(cnt)
  for tp in ('T1', 'T2', 'T3')
) piv

请参阅SQL Fiddle with Demo

如果要转换的值数量未知,则可以创建一个过程来生成此动态版本:

CREATE OR REPLACE procedure dynamic_pivot(p_cursor in out sys_refcursor)
as
    sql_query varchar2(1000) := 'select usr ';

    begin
        for x in (select distinct tp from temp order by 1)
        loop
            sql_query := sql_query ||
              ' , sum(case when tp = '''||x.tp||''' then cnt else 0 end) as '||x.tp;

                dbms_output.put_line(sql_query);
        end loop;

        sql_query := sql_query || ' from temp group by usr';

        open p_cursor for sql_query;
    end;
/

然后执行代码:

variable x refcursor
exec dynamic_pivot(:x)
print x

所有版本的结果都是相同的:

| USR | T1 | T2 | T3 |
----------------------
|   1 | 17 |  0 |  0 |
|   2 |  0 | 21 |  1 |
|   3 | 45 |  0 |  0 |

编辑:根据您的评论,如果您想要一个Total字段,最简单的方法是将查询放在另一个SELECT类似的内容中:

select usr,
  T1 + T2 + T3 as Total,
  T1,
  T2,
  T3
from
(
  select usr,
    sum(case when tp ='T1' then cnt else 0 end) T1,
    sum(case when tp ='T2' then cnt else 0 end) T2,
    sum(case when tp ='T3' then cnt else 0 end) T3
  from temp
  group by usr
) src;

请参阅SQL Fiddle with Demo