Question

我运行了以下查询，该查询返回36行数据

SELECT 
    A.OBJECTIVE, SUM(A.T_VALUE)
FROM 
    DB2ADM2.TFINTR10 A
WHERE 
    (A."YEAR" =10)
    AND (A.OBJECTIVE BETWEEN 'WAAAA' AND 'WZZZZ')
GROUP BY 
    A.OBJECTIVE


When I merge with another table and add the Narration field (OB_Narr5) the rows of data are reduced as the Ob_Narr5 does not exist for every Objective, see sql.

    SELECT A.OBJECTIVE, SUM ( A.T_VALUE ), B.OB_NARR5
    FROM DB2ADM2.TFINTR10 A INNER JOIN DB2ADM2.TFINOBJP B ON B.OB_12345 = A.
         OBJECTIVE
    WHERE (A."YEAR" =10)
    AND A.OBJECTIVE BETWEEN 'WAAAA' AND 'WZZZZ'
    GROUP BY A.OBJECTIVE, B.OB_NARR5

The rows returned are now only 4.

How can I return all the rows including the blank fields and / or return just the rows with the blank fields?

感谢回复，Left和Full Outer Join都有效。

How do I replace the <NULL> with a blank instead please?

WAAAA   -173597.12  <NULL>
WABAA   222717.76   GENERAL

Answer 1

使用LEFT JOIN而非INNER JOIN不会删除包含空列的左表的条目

Answer 2

select A.OBJECTIVE
    ,SUM(A.T_VALUE)
    ,B.OB_NARR5
from DB2ADM2.TFINTR10 A
left join DB2ADM2.TFINOBJP B on B.OB_12345 = A.OBJECTIVE
where A."YEAR" = 10
    and A.OBJECTIVE between 'WAAAA' and 'WZZZZ'
group by A.OBJECTIVE
    ,B.OB_NARR5

Answer 3

您可以使用完全外部联接来保留两个表中的值或任何特定表的左外连接

如果SQL中的列为空，则返回空白数据

3 个答案: