select b.*,a.Author_Name from book b
inner join (
select Author_ID,Author_Name from Authors
where Author_Age<(select avg(Author_Age) from Authors)) a
on a.Author_ID=b.Author_ID
inner join (
select Author_ID,Author_Name from Authors
where Author_Age<(select avg(Author_Age) from Authors)) a
on a.Author_ID=b.Author_ID
解决方案 »
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