动态Oracle Pivot_In_Clause

Question

我有点卡住了。我想做一个用户-角色-关系透视表，到目前为止，我的查询看起来像这样：

WITH PIVOT_DATA AS (
     SELECT *
     FROM
     (
         SELECT USERNAME, GRANTED_ROLE
         FROM DBA_USERS@DB_LINK U LEFT OUTER JOIN DBA_ROLE_PRIVS@DB_LINK R
         ON U.USERNAME = R.GRANTEE
      )
)
SELECT *
FROM PIVOT_DATA
PIVOT
(
    COUNT(GRANTED_ROLE)
    FOR GRANTED_ROLE
    IN('CONNECT') -- Just an example
)
ORDER BY USERNAME ASC;

它工作得很好，可以完成工作，但我不想写任何我想在pivot_in_clause中搜索的角色，因为我们有很多这样的角色，我不想每次都检查是否有任何变化。

那么有没有一种在pivot_in_clause中编写SELECT的方法呢？我自己试过了：

[...]
PIVOT
(
    COUNT(GRANTED_ROLE)
    FOR GRANTED_ROLE
    IN( SELECT ROLE FROM DBA_ROLES@DB_LINK )
)
[...]

但是它总是在整个查询的第一行给出一个ORA-00936："missing expression“，我不知道为什么。pivot_in_clause中不能有SELECT吗?还是我做错了？

Answer 1

你可以在你的脚本中构建动态查询，看看这个例子：

variable rr refcursor

declare 
  bb varchar2(4000);
  cc varchar2( 30000 );
begin 
    WITH PIVOT_DATA AS (
         SELECT *
         FROM
         (
             SELECT USERNAME, GRANTED_ROLE
             FROM DBA_USERS U LEFT OUTER JOIN DBA_ROLE_PRIVS R
             ON U.USERNAME = R.GRANTEE
          )
    )
    select ''''|| listagg( granted_role, ''',''' ) 
            within group( order by granted_role ) || '''' as x 
    into bb
    from (
      select distinct granted_role from pivot_data
    )
    ;

    cc := q'[
    WITH PIVOT_DATA AS (
         SELECT *
         FROM
         (
             SELECT USERNAME, GRANTED_ROLE
             FROM DBA_USERS U LEFT OUTER JOIN DBA_ROLE_PRIVS R
             ON U.USERNAME = R.GRANTEE
          )
    )
    SELECT *
    FROM PIVOT_DATA
    PIVOT
    (
        COUNT(GRANTED_ROLE)
        FOR GRANTED_ROLE
        IN(]'  || bb || q'[) -- Just an example
    )
    ORDER BY USERNAME ASC]';

    open :rr for cc;
end;
/

SET PAGESIZE 200
SET LINESIZE 16000
print :rr

下面是结果(只有很小的片段，因为它很宽很长)

-----------------------------------------------------------------------------------------------------------------------------------
    USERNAME                       'ADM_PARALLEL_EXECUTE_TASK' 'APEX_ADMINISTRATOR_ROLE' 'AQ_ADMINISTRATOR_ROLE' 'AQ_USER_ROLE'        
    ------------------------------ --------------------------- ------------------------- ----------------------- ----------------------
    ANONYMOUS                      0                           0                         0                       0          
    APEX_030200                    0                           0                         0                       0        
    APEX_PUBLIC_USER               0                           0                         0                       0    
    APPQOSSYS                      0                           0                         0                       0   
..............
    IX                             0                           0                         1                       1  
    OWBSYS                         0                           0                         1                       1