sql-server - 将 SQL Server Apply 查询迁移到 Oracle

Question

Oracle 中的以下 Sql Server 查询应等效于什么:

select dd.dname, e.ename
from emp e
outer apply 
(select top 1 dname from dept d where d.did=e.did order by bdate) dd

请注意，实际查询非常不同，但概念相同。请原谅我在上述查询中的任何语法错误。

我尝试了以下 Oracle 查询:

select dd.dname, e.ename
from emp e
left join 
(select * from 
(select dname from dept d where d.did=e.did order by bdate)
where rownum=1) dd

但是，它给出了以下错误:

Error at Command Line:6 Column:18
Error report:
SQL Error: ORA-00905: missing keyword
00905. 00000 -  "missing keyword"
*Cause:    
*Action:

Answer 1

加入后缺少 On 子句。因此，我按查询将查询转换为组，它起作用了:

select dd.dname, e.ename
from emp e
left join 
(select min(bdate), dname, did from dept d group by dname, did)dd
on dd.did=e.did