Question

Oracle的sql查询报错： ORA-00923未找到要求的 FROM 关键字，求大神帮忙看看哪里有问题！！

select a ,max(a1),max(a2)
from (
select a, case when b = '语文' then c else null end as a1,
b = '数学' then c else null end as a2
from
(select name a,subject b,score c from studentinfo) x
) y
group by a;

Answer 1

select a, max(a1), max(a2)
from (select a,
case
when b = '语文' then
c
else
null
end as a1,
case
when b = '数学' then
c
else
null
end as a2
from (select name a, subject b, score c from studentinfo) x) y
group by a;

Answer 2

select a, case when b = '语文' then c else null end as a1,
case when b = '数学' then c else null end as a2

Answer 3

b = '数学' then c else null end as a2这句开头也要case when