顯示記錄不匹配在哪裏條款

Question

我需要顯示不匹配where子句的記錄。

實施例 - select * from citytable where city in ('aa','bb','cc', 'dd','ee');

僅aa，bb，cc存在於表格中，dd & ee不存在於表格中。不過，我仍然需要顯示dd & ee。

Answer 1

您可能正在尋找這樣的事情。 IN條件與包含IN列表中唯一（不同）值的表的內部連接相同。你想要的是一個外連接。您需要有一個表格而不是IN列表。在下面的解決方案中，我將展示如何在運行中創建此「幫助程序」表;還有其他幾種方法，這只是表明了這個想法。

select deptno, ename from emp where deptno in (10, 50, 80); 

DEPTNO ENAME 
------ ------ 
10  CLARK 
10  KING 
10  MILLER 


with h (deptno) as (
    select 10 from dual union all 
    select 50 from dual union all 
    select 80 from dual 
) 
select h.deptno, e.ename 
from h left outer join emp e 
on h.deptno = e.deptno 
; 

DEPTNO ENAME 
------ ------ 
10  CLARK 
10  KING 
10  MILLER 
50 
80 

Answer 2

我不確定你想要輸出的樣子。如果沒有城市='ee'的數據，你想要展示什麼？像這樣？

SELECT * FROM 
(SELECT key AS A_key, one AS A_one, two AS A_two FROM cityTable WHERE one='aa') AS A 
JOIN 
(SELECT key AS E_key, one AS E_one, two AS E_two FROM cityTable WHERE one='ee') AS E 
ON A_key=E_key 
...etc. 

編輯：也許這是它：

Answer 3

當我明白你說的'dd' AMD 'ee'不存在於表，但你仍然需要它，就可以使用union all實現它。但請記住，「DD」和「EE」行的列將始終爲空，因爲沒有存在的記錄在你的citytable

SELECT ct.col1 AS city, ct.col2.....<all columns of your table> 
    from citytable ct 
    where city in ('aa','bb','cc') 
    UNION ALL 
    select 'dd' as city,null ,null.....<nulls as many times as the number of columns of your table> 
    from citytable ct1 
    UNION ALL 
    select 'ee' as city,null ,null.....<nulls as many times as the number of columns of your table> 
    from citytable ct2