我有三张桌子: menu_tab有列(menu_id,menu_description) item_tab有列(item_id,item_name,item_description,item_price) menu_has_item有列{(menu_tab_menu_id --->这是menu_id的外键(menu_tab中的pk)),item_tab_item_id ---是item_id的外键(item_tab中的pk))4
将会遇到两种重复 1)在同一menu_description中重复项目 2)项目副本在不同的菜单描述
示例:午餐菜单中有两个鸡肉三明治。午餐中的一个鸡肉三明治和晚餐菜单中的另一个鸡肉三明治_description
menu_tab
menu_id menu_description
1 lunch
2 dinner
3 Specials
item_tab
item_id item_description
1 b
2 d
3 g
4 x
5 g delete g
6 d
7 e
8 b delete b
9 x
menu_has_tab
menu_tab_menu_id item_tab_item_id
1个............................ 1
1个............................ 2
1个............................ 3
1个............................ 4
2 ............................ 5替换为3
2个............................ 6
3个............................ 7
3 ............................ 8替换为1
3 ............................ 9
如何在删除重复项后使用替换后的值更新menu_has_item?
答案 0 :(得分:1)
begin
for x in (
-- find duplicate items
select *
from (select rowid row_id,
item_id,
item_description,
row_number() over(partition by item_description order by
item_description) row_no
from item_tab)
where row_no > 1) loop
-- replaceing duplicate Items
update menu_has_item
set menu_has_item.item_tab_item_id =
( select item_id
from (select item_id,
row_number() over(partition by item_description order by
item_description) row_no
from item_tab where
item_tab.item_description = x.item_description)
where row_no = 1)
where menu_has_item .item_tab_item_id = x.item_id;
-- deleting duplicate items
delete item_tab where rowid = x.row_id;
end loop;
-- commit;
end;
答案 1 :(得分:0)
首先,您需要使用新值
替换menu_tab中的重复项merge into menu_tab dest
using (select *
from (select item_id, min(item_id) over(partition by item_description) as new_item_id from item_tab)
where item_id != new_item_id) src
on (dest.item_tab_item_id = src.item_id)
when matched then
update set dest.item_tab_item_id = new_item_id;
之后,您需要从项目表中删除重复项 你可以在那里找到脚本 http://sprogram.com.ua/en/articles/oracle-delete-duplicate-record
你把问题标记为plsql并且我认为你关于甲骨文,对不起。 但我在MySQL中存在合并声明 祝你好运答案 2 :(得分:0)
我为我的表Rout(RoutID,SourceCityID,DestCityID)和Form(FormID,RoutID,...)做了这个
我删除了表Rout中的重复路径并更新了Form表中的RoutID
首先获取按要复制的列
(SELECT * FROM
Rout,
(SELECT MIN(RoutID) MinRoutID
FROM Rout,
(SELECT SourceCityID,DestCityID
FROM Rout
GROUP BY SourceCityID,DestCityID
HAVING count(*) > 1) AS Duplicates
WHERE Rout.SourceCityID=Duplicates.SourceCityID AND Rout.DestCityID=Duplicates.DestCityID
GROUP BY Rout.SourceCityID,Rout.DestCityID)AS MRCols
WHERE RoutID=MinRoutID)AS DuplicateGroup
然后获取所有重复的行而不进行分组,并使用将要比较重复的列
(SELECT RoutID,Rout.SourceCityID,Rout.DestCityID FROM Rout,
(SELECT SourceCityID,DestCityID
FROM Rout
GROUP BY SourceCityID,DestCityID
HAVING count(*) > 1)AS Duplicates
WHERE Rout.SourceCityID=Duplicates.SourceCityID AND Rout.DestCityID=Duplicates.DestCityID)AS DuplicateDetail
然后更新表格tbl,如下所示:
UPDATE Form SET RoutID=DuplicateGroup.RoutID
FROM
Form,
(SELECT * FROM
Rout,
(SELECT MAX(RoutID) MinRoutID
FROM Rout,
(SELECT SourceCityID,DestCityID
FROM Rout
GROUP BY SourceCityID,DestCityID
HAVING count(*) > 1) AS Duplicates
WHERE Rout.SourceCityID=Duplicates.SourceCityID AND Rout.DestCityID=Duplicates.DestCityID
GROUP BY Rout.SourceCityID,Rout.DestCityID)AS MRCols
WHERE RoutID=MinRoutID)AS DuplicateGroup
,
(SELECT RoutID,Rout.SourceCityID,Rout.DestCityID FROM Rout,
(SELECT SourceCityID,DestCityID
FROM Rout
GROUP BY SourceCityID,DestCityID
HAVING count(*) > 1)AS Duplicates
WHERE Rout.SourceCityID=Duplicates.SourceCityID AND Rout.DestCityID=Duplicates.DestCityID)AS DuplicateDetail
WHERE
Form.RoutID=DuplicateDetail.RoutID AND
DuplicateGroup.SourceCityID=DuplicateDetail.SourceCityID
AND DuplicateGroup.DestCityID=DuplicateDetail.DestCityID
现在删除Rout中不在表格
中的行DELETE FROM Rout WHERE RoutID NOT IN(SELECT DISTINCT RoutID FROM Form)