Question

当列类型是集合时，是否可以将行转置为列？

请考虑以下事项：

CREATE TABLE dept (dept_no number(1), job_id  VARCHAR2(2), VALUE  VARCHAR2(1)) 

INSERT INTO dept
select 2 dept_no,'J1' jobid, 'X' VALUE  from dual
union all
select 2 dept_no,'J2' jobid, 'Y' VALUE  from dual
union all
select 2 dept_no,'J2' jobid, 'Z' VALUE  from dual
union all
select 3 dept_no,'J1' jobid, 'Y' VALUE  from dual
union all
select 3 dept_no,'J1' jobid, 'X' VALUE  from dual
union all
select 3 dept_no,'J2' jobid,'X' VALUE from dual
union all
select 3 dept_no,'J3' jobid,'Z' VALUE  from dual
union all
select 3 dept_no,'J3' jobid,'X' VALUE  from dual
union all
select 3 dept_no,'J3' jobid,'Y' VALUE  from dual

CREATE OR REPLACE TYPE v_t AS TABLE OF VARCHAR2(1);

我无法使用MAX OR MIN对集合进行分组。

select dept_no,
   decode(job_id,'J1',valueList) J1,
   decode(job_id,'J2',valueList) J2,
   decode(job_id,'J3',valueList) J3
from (SELECT dept_no, job_Id, CAST(COLLECT(VALUE) AS v_t ) AS valueList
FROM dept
GROUP BY dept_no, job_Id)

输出：

       DEPT_NO J1                 J2                 J3
    ---------- ------------------ ------------------ ------------------
             2 V_T('X')
             2                    V_T('Y', 'Z')
             3 V_T('Y', 'X')
             3                    V_T('X')
             3                                       V_T('Z', 'Y', 'X')

预期产出：

DEPT_NO J1                J2                J3
---------- ----------------- ----------------- --------------------
         2 V_T('X')          V_T('Y', 'Z')     V_T()
         3 V_T('Y', 'X')     V_T('X')          V_T('Z', 'Y', 'X')

dept_no可能是组列吗？

更新：抱歉，我找到了答案

   SELECT dept_no, CAST(COLLECT(decode(job_id, 'J1', VALUE, NULL)) AS v_t) J1,
   CAST(COLLECT(decode(job_id, 'J2', VALUE, NULL)) AS v_t) J2,
   CAST(COLLECT(decode(job_id, 'J3', VALUE, NULL)) AS v_t) J3
   FROM   dept
   GROUP  BY dept_no

将行转置为列值类型为集合的列

0 个答案: