ORACLE SQL DEVELOPER-select count(*) from multiple databases

Question

我如何从两个不同的数据库（称为 ZEOTA 和 SP）中选择 count(*)，结果如下：

Zeota SP
  88  3

我试过这个：

SELECT COUNT(CONSTRAINT_TYPE) NumberOfPrimaryKeys_Zeota 
FROM ALL_CONSTRAINTS
WHERE CONSTRAINT_TYPE = 'P' 
AND 
OWNER = 'ZEOTA';
SELECT COUNT(*) AS NumberOfAttributes_SP
FROM ALL_COL_COMMENTS
WHERE OWNER = 'SP';

但输出显示两个单独的查询结果：

Query result 1: 
    Zeota
      88
Query Result 2:
      SP
      3

但是我正在尝试这样做，但是遇到了问题：

SELECT 
COUNT(DISTINCT TABLE_NAME) AS ZNumOfTables,
COUNT(DISTINCT TABLE_NAME) AS SNumOfTables,
COUNT(DISTINCT TABLE_NAME) AS PNumOfTables
FROM ALL_TAB_COLUMNS
WHERE OWNER = 'SP';
WHERE OWNER = 'ZEOTA';

Answer 1

一种选择是将您当前的查询用作 CTE，然后交叉连接它们：

with
t1 as 
  (select count(constraint_type) num_pk_zeota
   from all_constraints
   where owner = 'ZEOTA'
     and constraint_type = 'PK'
  ),
t2 as
  (select count(*) num_attr_sp
   from all_col_comments
   where owner = 'SP'
  )
select a.num_pk_zeota,
       b.num_attr_sp
from t1 a cross join t2 b;

附：您所说的“数据库”是 Oracle 中的用户（模式）。