DB2 SQL更新与子查询相关的多于1列[duplicate]

Question

这个问题在这里已有答案：

• SQL update from one Table to another based on a ID match IN db2 6个答案

我是DB2的新手，但不是SQL的新手，也是DB2 LUW V9.5中与子查询相关的新的DB2 SQL更新。我的表如下： 在第3行和第7行，我需要更新第4和第8行（SCD）中的ACTIVE = 0和VALID_TO = VALID_FROM。我使用下面的Statement选择数据：

SELECT T2.COL1, T2.COL1_HIST, T2.ACTIVE, T2.VALID_FROM, T2.VALID_TO, T3.VALID_FROM
FROM TMP.TABLE01 T2 INNER JOIN 
(
    SELECT COL1, MAX(COL1_HIST) MAX_HIST FROM TMP.TABLE01 WHERE 
    ACTIVE = 1
    GROUP BY COL1
    HAVING Count(*)>1
)T1 ON T2.COL1 = T1.COL1 AND T2.COL1_HIST < T1.MAX_HIST
INNER JOIN TMP.TABLE01 T3 ON T1.COL1 = T3.COL1 AND T1.MAX_HIST = T3.COL1_HIST
WHERE T2.ACTIVE = 1

要在SQL世界中更新，我可以使用以下语句：

UPDATE T2 SET T2.ACTIVE = 0,T2.VALID_TO=T3.VALID_FROM
FROM TMP.TABLE01 T2 INNER JOIN 
(
    SELECT COL1, MAX(COL1_HIST) MAX_HIST FROM TMP.TABLE01 WHERE 
    ACTIVE = 1
    GROUP BY COL1
    HAVING Count(*)>1
)T1 ON T2.COL1 = T1.COL1 AND T2.COL1_HIST < T1.MAX_HIST
INNER JOIN TMP.TABLE01 T3 ON T1.COL1 = T3.COL1 AND T1.MAX_HIST = T3.COL1_HIST
WHERE T2.ACTIVE = 1

这怎么可能在DB2（DB2 LUW V9.5）世界中？ 我知道Stack Overflow中的类似问题，但它对我没有帮助:( link

提前谢谢了

Answer 1

试试这个：

merge into table01 a using 
(
select rownumber() over(partition by col1 order by col1_hist desc) rn_, t.* 
from table01 t
where active=1
) m on m.rn_=1 and a.active=1 and a.col1=m.col1 and a.col1_hist<>m.col1_hist
when matched then update set active=0, valid_to=m.valid_from;

内部子选择的rn_列具有值1，每行具有最高col1_hist，在具有相同col1的记录组中。 我们更新除了这些行之外的所有其他活动行，每个组具有正确的valid_from值。