以 Oracle 10g 为中心
我正在使用 oracle 10g.我有一个临时表 TEMP.
I am using oracle 10g. I have a temp table TEMP.
TEMP 的结构如下:-
TEMP has following structure:-
USER COUNT TYPE
---- ----- ----
1 10 T1
2 21 T2
3 45 T1
1 7 T1
2 1 T3
我需要一个查询来显示所有类型都有列名，类型可以有任何值，如 T1, T2,..Tn 并且结果将是:-
I need a query which will show all types has column names,and types can have any value like T1, T2,..Tn and result will be like:-
USER T1 T2 T3
---- -- -- --
1 17 0 0
2 0 21 1
3 45 0 0
和 User 列将显示所有用户，T1, T2 列将显示类型的总数.
and User column will show all the users and T1, T2 column will show total count of types.
推荐答案
在 Oracle 10g 中，没有 PIVOT 函数，但您可以使用带有 CASE:
In Oracle 10g, there was no PIVOT function but you can replicate it using an aggregate with a 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;
参见 SQL Fiddle with Demo
如果你有 Oracle 11g+ 那么你可以使用 PIVOT 函数:
If you have Oracle 11g+ then you can use the PIVOT function:
select *
from temp
pivot
(
sum(cnt)
for tp in ('T1', 'T2', 'T3')
) piv
参见 SQL Fiddle with Demo
如果您有未知数量的值要转换，那么您可以创建一个过程来生成它的动态版本:
If you have an unknown number of values to transform, then you can create a procedure to generate a dynamic version of this:
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一样的:
The result for all versions is the same:
| USR | T1 | T2 | T3 |
----------------------
| 1 | 17 | 0 | 0 |
| 2 | 0 | 21 | 1 |
| 3 | 45 | 0 | 0 |
根据您的评论，如果您想要 Total 字段，最简单的方法是将查询放在另一个 SELECT 中，类似于:
Based on your comment if you want a Total field, the easiest way is to place the query inside of another SELECT similar to this:
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;
参见 SQL Fiddle with Demo
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