问题
I have created a view that fills data from different tables. I used 10 select statements and combine the results of those select statements using UNION ALL.
I want to add primary key column to my view. because I have to create XML file using data in this view. so I need a primary key column for some process in my XML building application.
I have add rownum to all my select statements. But it returned duplicate ids. because rownum in each select statements start from 1.
Then I have created a sequence and tried use nextval . But I can't use sequence because my select statements has group by and order by.
Is there any way to do that ?
回答1:
You can do a select over the union, for example:
SELECT rownum(),*
FROM (SELECT * FROM tableA UNION ALL SELECT * FROM tableB)
UPDATED
SELECT rownum, t.*
FROM (SELECT * FROM tableA UNION ALL SELECT * FROM tableB) t
来源：https://stackoverflow.com/questions/14229056/oracle-create-a-view-with-auto-increment-id-column