我有一个看起来像这样的表:
C_ID P_ID KEY VALUE
null null KEY1 VALUE1
null null KEY2 VALUE2
null null KEY3 VALUE3
2 2 KEY4 VALUE4
2 3 KEY5 VALUE5
我想得到这个结果表/视图:
C_ID P_ID KEY1 KEY2 KEY3 KEY4 KEY5
NULL NULL VALUE1 VALUE2 VALUE3 NULL NULL
2 2 NULL NULL NULL VALUE4 NULL
2 3 NULL NULL NULL NULL VALUE5
有人知道如何实现这一目标吗? 我试过了:
select * from (select c_id, p_id, r_key, r_value from s_projectroles) pivot (max(r_value) for r_key in (any));
我收到了一个错误:
ORA-00936: Ausdruck fehlt
00936. 00000 - "missing expression"
答案 0 :(得分:10)
这可以通过以下方式动态完成。首先,这是查询的静态版本,因此您可以看到最终的sql:
select c_id,
p_id,
max(case when r_key= 'KEY1' then r_value end) KEY1,
max(case when r_key= 'KEY2' then r_value end) KEY2,
max(case when r_key= 'KEY3' then r_value end) KEY3,
max(case when r_key= 'KEY4' then r_value end) KEY4,
max(case when r_key= 'KEY5' then r_value end) KEY5
from s_projectroles
group by c_id, p_id
然后,要动态执行此操作,您可以创建以下过程:
CREATE OR REPLACE procedure dynamic_pivot(p_cursor in out sys_refcursor)
as
sql_query varchar2(1000) := 'select c_id, P_id ';
begin
for x in (select distinct r_key from s_projectroles order by 1)
loop
sql_query := sql_query ||
' , max(case when r_key = '''||x.r_key||''' then r_value end) as '||x.r_key;
dbms_output.put_line(sql_query);
end loop;
sql_query := sql_query || ' from s_projectroles group by c_id, p_id';
open p_cursor for sql_query;
end;
/
然后执行它:
variable x refcursor
exec dynamic_pivot(:x)
print x
结果是一样的:
| C_ID | P_ID | KEY1 | KEY2 | KEY3 | KEY4 | KEY5 |
----------------------------------------------------------------
| (null) | (null) | VALUE1 | VALUE2 | VALUE3 | (null) | (null) |
| 2 | 2 | (null) | (null) | (null) | VALUE4 | (null) |
| 2 | 3 | (null) | (null) | (null) | (null) | VALUE5 |