这是我写的 codeselect distinct a.author_institution \
from author a \
full join co_author\
on a.author_id = co_author.author_id\
full join paper\
on paper.paper_id = co_author.paper_id\
where a.author_id in(select a1.author_id \
from \
author a1 \
full join co_author\
on a1.author_id = co_author.author_id\
full join paper\
on paper.paper_id = co_author.paper_id\
where paper.paper_year = '2002' \
and paper.paper_conference LIKE 'SIGMOD' )\
group by a.author_institution ;")); 运行有错误但把 group by 去掉就好了 distinct 好像也不能用不知道为什么补充 group by 和distinct 可以对主码 但对其它项不行
from author a \
full join co_author\
on a.author_id = co_author.author_id\
full join paper\
on paper.paper_id = co_author.paper_id\
where a.author_id in(select a1.author_id \
from \
author a1 \
full join co_author\
on a1.author_id = co_author.author_id\
full join paper\
on paper.paper_id = co_author.paper_id\
where paper.paper_year = '2002' \
and paper.paper_conference LIKE 'SIGMOD' )\
group by a.author_institution ;")); 运行有错误但把 group by 去掉就好了 distinct 好像也不能用不知道为什么补充 group by 和distinct 可以对主码 但对其它项不行
from author a
full join co_author
on a.author_id = co_author.author_id
full join paper
on paper.paper_id = co_author.paper_id
where a.author_id in(
select a1.author_id
from author a1
full join co_author
on a1.author_id = co_author.author_id
full join paper
on paper.paper_id = co_author.paper_id
where paper.paper_year = '2002'
and paper.paper_conference LIKE 'SIGMOD' )
from author a
full join co_author
on a.author_id = co_author.author_id
full join paper
on paper.paper_id = co_author.paper_id
where a.author_id in(
select a1.author_id
from author a1
full join co_author
on a1.author_id = co_author.author_id
full join paper
on paper.paper_id = co_author.paper_id
where paper.paper_year = '2002'
and paper.paper_conference LIKE 'SIGMOD' )
group by a.author_institution