如何使用'as'关键字为Oracle中的表添加别名? [英] How to use the 'as' keyword to alias a table in Oracle?

问题描述

我正在尝试在Oracle SQL Developer中执行此查询:

SELECT G.Guest_ID, G.First_Name, G.Last_Name
FROM Guest AS G
  JOIN Stay AS S ON G.Guest_ID = S.Guest_ID
WHERE G.City = 'Miami' AND S.Room = '222';

但是，出现以下错误:

ORA-00933: SQL command not properly ended
00933. 00000 - "SQL command not properly ended"
*Cause:
*Action:
Error at Line: 2 Column: 12

我在第2行中看不到任何问题，并且该错误的描述性不是很高.它似乎与as关键字有关.如果我删除它，它可以正常工作.但是，我希望我的查询非常详细.因此，我必须找出一种解决问题的方法，而不必删除as关键字.

这是涉及的表的结构:

CREATE TABLE GUEST
(
  GUEST_ID       NUMBER               NOT NULL,
  LAST_NAME      VARCHAR2(50 BYTE),
  FIRST_NAME     VARCHAR2(50 BYTE),
  CITY           VARCHAR2(50 BYTE),
  LOYALTY_NUMBER VARCHAR2(10 BYTE)    
);

CREATE TABLE STAY
(
  STAY_ID        NUMBER                         NOT NULL,
  GUEST_ID       NUMBER                         NOT NULL,
  HOTEL_ID       NUMBER                         NOT NULL,
  START_DATE     DATE,
  NUMBER_DAYS    NUMBER, 
  ROOM           VARCHAR2(10 BYTE)
);

非常感谢您提前提供帮助.

解决方案

您可以在许多SQL服务器(至少是MsSQL，MySQL，PostrgreSQL)上使用AS进行表别名，但是它始终是可选的，而在Oracle上则是非法的. /p>

因此删除AS:

SELECT G.Guest_ID, G.First_Name, G.Last_Name
FROM Guest G

I'm trying to execute this query in Oracle SQL Developer:

SELECT G.Guest_ID, G.First_Name, G.Last_Name
FROM Guest AS G
  JOIN Stay AS S ON G.Guest_ID = S.Guest_ID
WHERE G.City = 'Miami' AND S.Room = '222';

However, I get the following error:

ORA-00933: SQL command not properly ended
00933. 00000 - "SQL command not properly ended"
*Cause:
*Action:
Error at Line: 2 Column: 12

I don't see any problem in line 2 and the error is not very descriptive. It appears to be something to do with the as keyword. If I remove it, it works fine. However, I want my queries to be very verbose. Therefore, I must figure out a way to fix whatever the problem is without removing the as keyword.

This is the structure of the tables involved:

CREATE TABLE GUEST
(
  GUEST_ID       NUMBER               NOT NULL,
  LAST_NAME      VARCHAR2(50 BYTE),
  FIRST_NAME     VARCHAR2(50 BYTE),
  CITY           VARCHAR2(50 BYTE),
  LOYALTY_NUMBER VARCHAR2(10 BYTE)    
);

CREATE TABLE STAY
(
  STAY_ID        NUMBER                         NOT NULL,
  GUEST_ID       NUMBER                         NOT NULL,
  HOTEL_ID       NUMBER                         NOT NULL,
  START_DATE     DATE,
  NUMBER_DAYS    NUMBER, 
  ROOM           VARCHAR2(10 BYTE)
);

Thanks for any help in advance.

解决方案

You can use AS for table aliasing on many SQL servers (at least MsSQL, MySQL, PostrgreSQL) but it's always optional and on Oracle it's illegal.

So remove the AS :

SELECT G.Guest_ID, G.First_Name, G.Last_Name
FROM Guest G

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