情景:
student id stname sex
score scoreid stname birth
course id coursename age
簡單說明 a,b ,c 三表a.name=b.name a.id=c.id
現在要查 id ,name ,course
有兩種方法:
select a.id,b.name,c. coursename from student a,score b,course c where a.name=b.name and a.id=c.courseid;
select a.id,b.name,c. coursename from student a inner join score b on a.name=b.name inner join course c on a.id=c.courseid;