在关键字 'group' 附近有语法错误.select sname from s,scwhere s.sno = sc.snoand sc.grade = nullhaving count(*) >= 2group by sc.sno

在关键字 'group' 附近有语法错误.select sname from s,scwhere s.sno = sc.snoand sc.grade = nullhaving count(*) >= 2group by sc.sno
在关键字 'group' 附近有语法错误.
select sname
from s,sc
where s.sno = sc.sno
and sc.grade = null
having count(*) >= 2
group by sc.sno

在关键字 'group' 附近有语法错误.select sname from s,scwhere s.sno = sc.snoand sc.grade = nullhaving count(*) >= 2group by sc.sno
select sname,sc.sno
from s,sc
where s.sno = sc.sno
and sc.grade = null
having count(*) >= 2
group by sc.sno