Question

sql 2个表查询（可能有空值），结果要全部显示

假设有
学生表a 成绩b
id name Student ID chsid stid chinese english
1 a x23 1 1 80 <null>
2 b s21 2 2 90 80
3 c b11 3 3 70 <null>

希望得到合并表st_course
id name Student ID chinese english
1 a x23 80 <NULL>
2 b s21 90 80
3 c b11 70 <NULL>

求问这么输出

Answer 1

select a.id,a.name,a.studentid,b.chinese,b.english
from a left join b on a.id=b.stid

Answer 2

select * from
(select a.*,b.chinese,b.english from a ,b where a.id = b.stid) st_course;