子查询Oracle

Question

我有LEFT JOIN的SELECT语句，连接表是子查询。 Oracle无法识别第二个子查询的别名。它适用于DB2，但不适用于Oracle。 我如何实现它或重写我的查询？

SELECT *                  
 FROM                                                      
 (SELECT     E.C3 AS  COLUMN3        
    , E.C4 AS  COLUMN4        
   FROM TBL_1 D                            
    , TBL_2 E                            
WHERE D.C6  =  E.C6 ) B                                                              
LEFT  JOIN  TABLE   
(SELECT  C.C1                          
 FROM    TBL_3  C                   
 WHERE                                                  
 C.C7            = 'hello'      
 AND B.C3            = C.C8                            
UNION ALL                                                 
 SELECT  C.C1                          
    FROM    TBL_3  C                
    WHERE                                               
    C.C7          = 'world'      
    AND B.C4          =  C.C8                       
    )            A               
ON 1 = 1

Oracle错误消息：      ORA-00904：＆＃34; B＆＃34;。＆＃34; C3＆＃34;：无效的标识符

Answer 1

您可以将此查询简化为以下内容，删除子查询：

Select      A.Col1, B.Col2
From        tbl_AJoin   A
Left Join   tbl_BJoin   B   On  A.col1 = B.col1

Answer 2

您遇到语法错误。这样：

select * from (select col1 from tbl_Ajoin) A
left join table (select col2 from tbl_Bjoin where A.col1 = tbl_Bjoin.col1) B     
ON 1 = 1

应该是这样的：

select * from (select col1 from tbl_Ajoin) A
left join (select col2 from tbl_Bjoin where A.col1 = tbl_Bjoin.col1) B     
ON 1 = 1

或更具体地说，这个：

left join table (select

不应该有table这个词。它应该是这样的：

left join (select