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Oracle Interview Questions

 
Greenhorn
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Hi All,
Recently I went for an interview and was asked some hard database question which they expected a Java developer to be able to answer.
Do you guys know the precise answers to these

1.How to delete 1 of the 2 duplicate rows in a table ?

There were ohter tough questions which i cannot recollect - but guys you can post and lets see i we get answers.

Cheers,
Gary
 
Ranch Hand
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Here's one way:I don't imagine that many Java developers would know that one.
 
ranger
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"Gary Nyc"-
Welcome to the JavaRanch! Please adjust your displayed name to meet the

JavaRanch Naming Policy.

You can change it

here.

Thanks! and welcome to the JavaRanch!

Mark
 
Gary Jones
Greenhorn
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That is a good way to do it - what if we do not have the rowid option,then is there a way.
 
author & internet detective
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"Gary N",
Thanks for updating the display name. Note that we require a last name, not just a last initial.

Thanks,
Jeanne
Oracle Forum Bartender
 
Ranch Hand
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I think rowid generated by database, so it will be there always.
And I also believe, many developer including didn't know the solution.
 
Greenhorn
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SQL> select * from new1;

NAME AGE
---------- ----------
pranay 20
pranay 20
pranay 20
ravi 20
ravi 20
ravi 20

6 rows selected.

SQL> delete from new1 a where a.rowid>(select min(b.rowid) from new1 b where a.name=b.name);

4 rows deleted.

SQL> select * from new1;

NAME AGE
---------- ----------
pranay 20
ravi 20

Cheers!!!
This is the solution
 
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"Pranay T.",

There aren't many rules that you need to worry about here on the Ranch, but one that we take very seriously regards the use of proper names. Please take a look at the JavaRanch Naming Policy and adjust your display name to match it.

In particular, your display name must be a first and a last name separated by a space character, and must not be obviously fictitious.

Thanks!
bear
JavaRanch Sheriff
 
Bibian Orchard
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Done!!!
 
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Originally posted by Jignesh Patel:
I think rowid generated by database, so it will be there always.
And I also believe, many developer including didn't know the solution.



I think Sql server doesn't have a rowid variable as it's available in Oracle. Is there any general solution for this ?
 
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