Question

如何将此sql server查询转换为Teradata查询。这在Teradata中不起作用。

select *, 
   (select top 1 endvalue 
    from #AUID 
    where #AUID.adate <= t.adate and #AUID.tid=t.tid 
    order by #AUID.adate desc) as AsD
from History_1 t

Answer 1

当涉及子查询时，您不能只有*。您应该使用tablename。*或别名。*（如果使用了别名）。

select t.*, 
   (select top 1 endvalue 
    from #AUID 
    where #AUID.adate <= t.adate and #AUID.tid=t.tid 
    order by #AUID.adate desc) as AsD
from History_1 t

但是，这会抛出 失败6916 TOP N语法错误：子查询 错误不支持前N个选项。

您可以尝试加入表格。

select
    t.*,
    a.endvalue
from 
    History_1 t
left outer join
    #AUID a
on a.tid = t.tid
and a.adate <= t.adate
qualify row_number() over (partition by t.tid, t.adate order by a.adate desc) = 1;  --this ensures you select only one row with max(adate)

Teradata错误：select *必须有from子句

1 个答案: