SQL在带where子句的select语句上左连接

Question

我试图像这样的选择语句左联接：

select *
from (select * from foo  where rownum <= 10 ) tab1
left join (select sum(total) total,sum(worker) worker from bars  where work_date between tab1.start_date and tab1.end_date ) tab2
on tab1.foo_id=tab2.id

我收到以下错误：

oci_execute（）：ORA-00904：“ tab1”。“ end_date”：无效的标识符

任何帮助，将不胜感激，谢谢！

Answer 1

一种执行所需操作的方法是使用两个相关的子查询：

select foo.*
     (select sum(b.total) as total, sum(worker) as worker
      from bars
      where b.work_date between foo.start_date and foo.end_date and
            foo.foo_id = b.id
     ) as total,
     (select sum(b.worker) as worker
      from bars b
      where b.work_date between foo.start_date and foo.end_date and
            foo.foo_id = b.id
     ) as worker
from foo
where rownum <= 10;

Answer 2

这也应该起作用：

select
   tab1.foo_id
  ,tab1.start_date
  ,tab1.end_date
  ,sum(tab2.total) as total
  ,sum(tab2.worker) as worker
from foo tab1
left join bars tab2
  on tab2.work_date between tab1.start_date and tab1.end_date
  and tab1.foo_id = tab2.id
where tab1.rownum <= 10
group by
   tab1.foo_id
  ,tab1.start_date
  ,tab1.end_date