执行时选择无效的标识符在oracle中选择

Question

我想在oracle中执行一个select使用3个表，nba_player，nba_team和nba_team_roster。 nba_player包含player_id的球员数据，nba_team包含team_id的球队信息。 nba_team_roster是一个关联实体，包含一个player_id和team_id来关联这两者。我想要这个查询返回团队'OKC'上每个玩家的名字和姓氏，但由于某种原因，它给了我下面的错误。我不知道为什么这不能正确执行。任何帮助将不胜感激。

select nba_player.first_name, nba_player.last_name 
from nba_player,nba_team 
join nba_team_roster 
on nba_team_roster.player_id=nba_player.player_id 
where nba_team_roster.team_id= nba_team.team_id 
and nba_team.team_name='OKC'; 


on nba_player.player_id=nba_team_roster.player_id 
    * 
ERROR at line 4: 
ORA-00904: "NBA_PLAYER"."PLAYER_ID": invalid identifier 

CREATE TABLE NBA_Team(
team_id number primary key, 
team_name varchar(5) 
); 

CREATE TABLE NBA_Player(
player_id number primary key, 
first_name varchar(10), 
last_name varchar (11), 
position varchar(3), 
salary number, 
points_per_game number 
); 

CREATE TABLE NBA_Team_Roster(
roster_ID number primary key, 
team_id number, 
player_id number unique, 
foreign key (team_id) references NBA_Team(team_id), 
foreign key (player_id) references NBA_Player(player_id) 
); 

Answer 1

规则很简单：在FROM子句中决不使用逗号。 始终使用使用正确的，明确的JOIN语法。这将解决您的问题，并使查询更容易理解：

select p.first_name, p.last_name 
from nba_player p join 
    nba_team_roster r 
    on r.player_id = p.player_id join 
    nba_team t 
    on r.team_id = t.team_id 
where t.team_name = 'OKC'; 

请注意，我还介绍了表别名。这些使查询更容易编写和阅读。