Question

这是一个在Transact-sql

中完美运行的SQL语句

SELECT a.Account_ID, a.First_Name, a.Last_Name, m.number
FROM Account a,
(SELECT R_Account_ID, COUNT(Notification_ID) AS number
FROM Rcv_Send_Event_Notf 
GROUP BY R_Account_ID) m
WHERE a.Account_ID = m.R_Account_ID

但它不在Oracle中。它在大多数select语句中抱怨m.number。我相信也是因为第3行的AS number。

user.table.column，table.column或列规范无效......

Oracle中的列别名有不同的方法吗？

感谢您的帮助

Answer 1

Number是Oracle中的关键字，因此如果不使用双引号，则无法将其用作别名。大多数人会建议不要将它用作别名，句号。

> select d.number from (select sysdate as number from dual) d

Error starting at line 3 in command:
select d.number from (select sysdate as number from dual) d
Error at Command Line:3 Column:9
Error report:
SQL Error: ORA-01747: invalid user.table.column, table.column, or column specification
01747. 00000 -  "invalid user.table.column, table.column, or column specification"

> select d.number from (select sysdate as "number" from dual) d

Error starting at line 2 in command:
select d.number from (select sysdate as "number" from dual) d
Error at Command Line:2 Column:9
Error report:
SQL Error: ORA-01747: invalid user.table.column, table.column, or column specification
01747. 00000 -  "invalid user.table.column, table.column, or column specification"

> select d."number" from (select sysdate as "number" from dual) d
number                    
------------------------- 
07-MAY-12 12:32:28 PM

Answer 2

如果我没有错过任何内容，你可以使用

select a.account_ID, a.First_Name, a.Last_Name, count(*)
from Account a
inner join RCV_Send_Event_Notf m on a.Account_Id = m.R_Account_Id
Group by a.account_Id, a.First_Name, a.Last_Name;

Answer 3

Oracle可能不喜欢名称“number”，因为它是一个关键字。我“简化”了查询并重命名为“数字”，它似乎正常工作

SELECT m.number_col
FROM dual a,
(SELECT   123 AS number_col
FROM dual ) m

您还可以使用WITH子句：

 WITH m AS
(SELECT  sysdate  as number_col
FROM dual )
SELECT m.number_col
FROM dual a, m

Oracle如何对内部select语句中的计算属性的列进行别名

3 个答案: