ORA-00904：“ DEPT_ID”：无效的标识符

Question

我检查了所有列名称，尝试删除该列并添加一个新列，但是我仍然收到此错误。我的SQL查询有问题吗？

  

ORA-00904：“ DEPT_ID”：无效的标识符

alter table Employ add foreign key (Dept_Id) references Department(Dept_ID);

Answer 1

类似这样的东西：

SQL> create table department (dept_id number primary key);

Table created.

SQL> create table employ (id         number primary key,
  2                       dept_id    number);

Table created.

SQL> alter table employ add constraint fk_ed foreign key (dept_id)
  2  references department (dept_id);

Table altered.

SQL>