Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17

x
?
Solved

query on rownum and rowid

Posted on 2010-08-18
1
Medium Priority
?
1,442 Views
Last Modified: 2012-05-10
Can anyone please advise on following questions-
-what is equivalent of rowid and rownum as we have in oracle
-what is a sql to get employee names who has second highest salary by department from employee table
-How can we delete duplicate rows from a table which has 5 columns and none of them is a primary key
-how the database execute following sql at back end- select min(price),productid from product where sale='CA' group by productid
0
Comment
Question by:sunilbains
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
1 Comment
 
LVL 37

Accepted Solution

by:
momi_sabag earned 2000 total points
ID: 33470963
depends on your version of db2
pre 9.7 - no equivalent, you can generate a row number using the row_number function, for example
select *
 from (select *, row_number() over(order by col1, col2) rownum from your_table ) t
where rownum < 100


select * from
 (select *, row_number() over(partition by department order by salary desc) rown from yourTable) t
where rown = 2

in order to delete you will have to copy to a new table a distinct of the records that has duplicates, delete all duplicates and copy back, for example

insert into temp_table
select col1,col2,col3,col4,col5
from yourTable
group by col1,col2,col3,col4,col5
having count(*) > 1

delete from yourTable t
where 1 < (select count(*) from yourTable where col1 = t.col1 and col2 = t.col2 and col3 = t.col3 and col4=t.col4 and col5=t.col5)

insert into yourTable select * from temp_table


if depends, if there is an index on productId, price it just probes every product and gets the min price,
otherwise it needs to sort by productId, price
0

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Recursive SQL in UDB/LUW (you can use 'recursive' and 'SQL' in the same sentence) A growing number of database queries lend themselves to recursive solutions.  It's not always easy to spot when recursion is called for, especially for people una…
Recursive SQL in UDB/LUW (it really isn't that hard to do) Recursive SQL is most often used to convert columns to rows or rows to columns.  A previous article described the process of converting rows to columns.  This article will build off of th…
Have you created a query with information for a calendar? ... and then, abra-cadabra, the calendar is done?! I am going to show you how to make that happen. Visualize your data!  ... really see it To use the code to create a calendar from a q…
In this video, Percona Solution Engineer Dimitri Vanoverbeke discusses why you want to use at least three nodes in a database cluster. To discuss how Percona Consulting can help with your design and architecture needs for your database and infras…
Suggested Courses

705 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question