从子查询

Question

选择，所以我有以下导致错误（对于那些有兴趣的：ORA-00904：“的Bleh”：无效的标识符）样本查询

select bleh from (
      SELECT MIN(mtb.id) KEEP (DENSE_RANK FIRST ORDER BY mtb.id) "bleh" 
       FROM mytable mtb 
      WHERE mtb.filtered_field_one = 0 
       and mtb.filtered_field_two = 0 
      GROUP BY mtb.foreighn_id, mtb.id 
); 

如果我把它变成（注一与*）取代bleh：

select * from (
      SELECT MIN(mtb.id) KEEP (DENSE_RANK FIRST ORDER BY mtb.id) "bleh" 
       FROM mytable mtb 
      WHERE mtb.filtered_field_one = 0 
       and mtb.filtered_field_two = 0 
      GROUP BY mtb.foreighn_id, mtb.id 
); 

我得到的结果完全按照我期望的那样从1日查询，它看起来像命名的Bleh以恰当的值1列。

那么为什么我不能选择该列的名称（别名）？

Answer 1

当您用"双引号将名称命名为列时，数据库需要按原样调用它，同时还使用双引号！因此，尝试这样的：即使我说as is我认为，@Stawros提供的评论是一个有价值的信息和平

select bleh from (
     SELECT MIN(mtb.id) KEEP (DENSE_RANK FIRST ORDER BY mtb.id) bleh 
      FROM mytable mtb 
     WHERE mtb.filtered_field_one = 0 
      and mtb.filtered_field_two = 0 
     GROUP BY mtb.foreighn_id, mtb.id 
); 

：

至于

select "bleh" from (
     SELECT MIN(mtb.id) KEEP (DENSE_RANK FIRST ORDER BY mtb.id) "bleh" 
      FROM mytable mtb 
     WHERE mtb.filtered_field_one = 0 
      and mtb.filtered_field_two = 0 
     GROUP BY mtb.foreighn_id, mtb.id 
); 

还是这样列命名在Oracle：

bleh = BLEH = Bleh 
but 
"bleh" <> "BLEH" <> "Bleh"