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Whether order of rows will be changed when its selected?


Whether order of rows will be changed when its selected?

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sharmili.net
sharmili.net
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Hi Everyone,

This is my table which have no primary key,My question is If I select this whether the order of rows will be changing?Or the same order will be displayed when we select?And what is the reason behind for this?

no sid
1 101
7 202
4 302
6 788
9 67
3 9080

Thanks in advance.

Sharmi
Koen Verbeeck
Koen Verbeeck
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Most of the time you will get the order in which the rows were inserted, unless you use indexes.
It is however not 100% garantueed that you will always get the same order.

Conclusion: order does not matter. If it does, use ORDER BY.


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Alan Burstein
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Just to add to what Koen said...
The only way to guarantee that rows are returned in a specific order is when ORDER BY is used.

It's also worth noting that ORDER BY is used more often than it is needed. Sorting is an expensive operation for SQL server, especially when dealing with millions of rows. I let the application that uses the data do the sorting whenever possible.

-- Alan Burstein


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Take a look at this article. http://blogs.msdn.com/b/conor_cunningham_msft/archive/2008/08/27/no-seatbelt-expecting-order-without-order-by.aspx

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