我创建了两个表格，
SQL> create table students
2(
3 st_idvarchar2(20),
4 namevarchar2(10),
5 agenumber(2),
6 tol_score number(3)
7) ;
SQL> insert into students values('973231','wangbindu',22,501);
SQL> insert into students values('973232','zhuzhijing',21,538);
SQL>insert into students values('973233','gaojing',21,576);
SQL>create table student_skill
2 (
3st_idvarchar2(20),
4skillvarchar2(20)
5);
SQL>insert into student_skill values('973231','篮球');
SQL>insert into student_skill values('973233','足球');
我想得到所有的学生信息如下：
st_id name age tol_score skill
973231wangbinde22
501
篮球
973232zhuzhijing 21
538
973233gaojing21
576
足球
我写的sql：alter table students add skill varchar2(20));
insert into students (skill) select skill from student_skillwhere students.st_id=student_skill.st_id;
语法错误：非法的ALTER。请问我如何写呢？还有如何删除表中的某一列呢？
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