Question

此刻，我正在使用Firebird与InterBase一起工作。我需要两次获得一个条件的记录，但是每次运行查询时，我都会不断收到错误消息。有没有一种方法可以解决InterBase中的交叉联接问题？是否有一种更简单的方法来解决这个逻辑添加到查询中。看来Firebird不会接受交叉加入。

SELECT EMPLOYEE_NAME, LAST_NAME, CACODE

FROM EMPLOYEESTABLE 

(
SELECT 889 AS CACODE, 8592-265-44444 AS STANDARDCACODE
UNION ALL 
SELECT 695 AS CACODE, 8554-265-44578 AS STANDARDCACODE
) C

Answer 1

选择始终需要from。表RDB$DATABASE返回带有数据库名称的1行，因此我们可以使用它。我想您正在寻找这样做：

SELECT EMPLOYEE_NAME, LAST_NAME, CACODE

FROM EMPLOYEESTABLE, 

(
SELECT 889 AS CACODE, '8592-265-44444' AS STANDARDCACODE FROM RDB$DATABASE
UNION ALL 
SELECT 695 AS CACODE, '8554-265-44578' AS STANDARDCACODE FROM RDB$DATABASE
) C

Answer 2

SELECT 
   889 AS CACODE, 
   /* '8592-265-44444' AS STANDARDCACODE, >>unused<< */ 
   EMPLOYEE_NAME, 
   LAST_NAME
FROM EMPLOYEESTABLE 

UNION ALL

SELECT 
   695 AS CACODE, 
   /* '8554-265-44578' AS STANDARDCACODE, >>unused<< */ 
   EMPLOYEE_NAME, 
   LAST_NAME
FROM EMPLOYEESTABLE

谁需要加入这样的简单查询：-D

交叉联接InterBase根据条件获取重复记录

2 个答案: