將SQL查詢轉換爲樞紐

Question

我似乎無法獲取將以下查詢轉換爲樞軸SQL的邏輯。我的表有20列與他們的角色，我想將這些列轉換成行，所以當導出到Excel時，我可以過濾一個列，因爲值可以在20列相同。到目前爲止，我所做的是轉換20列到一個單一的一個，然後拆分單一到行：

select  distinct TASKID, 
      regexp_substr(t.roles,'[^|]+', 1, lines.column_value) as role 
from  (
      select TASKID, 
         TRIM(ROLE1) || '|' || 
         TRIM(ROLE2) || '|' || 
         TRIM(ROLE3) || '|' || 
         TRIM(ROLE4) || '|' || 
         TRIM(ROLE5) || '|' || 
         TRIM(ROLE6) || '|' || 
         TRIM(ROLE7) || '|' || 
         TRIM(ROLE8) || '|' || 
         TRIM(ROLE9) || '|' || 
         TRIM(ROLE10) || '|' || 
         TRIM(ROLE11) || '|' || 
         TRIM(ROLE12) || '|' || 
         TRIM(ROLE13) || '|' || 
         TRIM(ROLE14) || '|' || 
         TRIM(ROLE15) || '|' || 
         TRIM(ROLE16) || '|' || 
         TRIM(ROLE17) || '|' || 
         TRIM(ROLE18) || '|' || 
         TRIM(ROLE19) || '|' || 
         TRIM(ROLE20) as roles 
      from  menu_roles 
      where  RLTYPE='58' 
     ) t, 
      TABLE(CAST(MULTISET(select LEVEL from dual connect by instr(t.roles, '|', 1, LEVEL - 1) > 0) as sys.odciNumberList)) lines 
where  regexp_substr(t.roles,'[^|]+', 1, lines.column_value) is not null 
order by regexp_substr(t.roles,'[^|]+', 1, lines.column_value) 

我會理解的，使用PIVOT會更有效率VS串聯和分裂的字符串。

謝謝！

Answer 1

你似乎想UNPIVOT：

SELECT task_id, 
     role 
FROM menu_roles 
UNPIVOT (role FOR role_number IN (ROLE1, ROLE2, ROLE3, ROLE4 /*, ... */)); 

或者，使用UNION ALL：

  SELECT task_id, role1 AS role FROM menu_roles 
UNION ALL SELECT task_id, role2 AS role FROM menu_roles 
UNION ALL SELECT task_id, role3 AS role FROM menu_roles 
UNION ALL SELECT task_id, role4 AS role FROM menu_roles 
-- ...