I think the reason nobody has replied is that the term "row number" does 
not really have any meaning in a DBMS. How the database stores rows 
inteneally is the DBMS's private business, and should not be visible to 
you. I think it is true that MySQL does not *have* an internal row number, 
so there is nothing to skip by. All it stores in MyISAM table is file 
offsets. However, even if I am wrong, it doesn't matter: that is an 
internal implementation detail and should not be visible to you.

However, if I read you rightly, what you want it to extract a random tenth 
of your table. You could do this by something like
SELECT <columns> FROM <table> ORDER BY rand() LIMIT <table size / 10> ;


Joćo Borsoi Soares <[EMAIL PROTECTED]> wrote on 23/11/2004 
11:30:26:

> No body has answered my question so far. Does that mean there is no way
> to retrieve current row numbers in a query or no way to retrieve results
> jumping steps?
> 
> I would appreciate any help.
> 
> Thanks,
> Joao.
> 
> -----Mensagem encaminhada-----
> > From: Joćo Borsoi Soares <[EMAIL PROTECTED]>
> > To: [EMAIL PROTECTED] <[EMAIL PROTECTED]>
> > Subject: row numbers, jumping rows
> > Date: Sun, 21 Nov 2004 11:23:41 -0200
> > 
> > Hello list,
> > 
> > I wonder if someone could help me to get the fastest result on my 
query.
> > I need to classify one entity, according to a specific attribute 
(let's
> > call it X), looking at a sample extracted from a database table. 
> > First I need to sort my sample ordered by a specific table field (X).
> > Then I should divide my sorted sample in 10 equal groups (same number 
of
> > rows). Finally, I should classify my entity (1 to 10), finding out at
> > which group its attribute X fits in.
> > 
> > Let me explain my thoughts. First I should make a "SELECT COUNT(*).." 
to
> > find the total number of rows in my sample. Then I make queries using
> > LIMIT until I find which group the X attribute fits in. In the worst
> > case I will have to do 10 queries. Which I think should take too long 
in
> > my case.
> > 
> > I wanted to make it in only one query. It could be possible if I could
> > make a query which returns result jumping rows, like "STEP N" where 
"N"
> > could be the number of items in each group. Is there anything in mysql
> > that can give me that? I also thought if I could have the row numbers 
in
> > the query result, I could solve it with a simple condition like, 
"WHERE
> > rowNum % N = 0".
> > 
> > Any ideas?
> > 
> > Thanks.
> > 
> > 
> > 
> 
> 
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