Hi i am trying to retrive data in chunks like 5 at a time or 10 at a
time. Can anyone guide me to tutorials on how to go about doing this.

Thanks

undbund wrote:
> Hi i am trying to retrive data in chunks like 5 at a time or 10 at a
> time. Can anyone guide me to tutorials on how to go about doing this.
>
> Thanks

5 pink pickles? 5 records? 5 columns? 5 words? 5 bytes?

On Apr 9, 9:05 pm, Michael Austin <maus...@firstdbasource.com> wrote:
> undbund wrote:
> > Hi i am trying to retrive data in chunks like 5 at a time or 10 at a
> > time. Can anyone guide me to tutorials on how to go about doing this.
>
> > Thanks
>
> 5 pink pickles? 5 records? 5 columns? 5 words? 5 bytes?

If it makes any difference, I vote for the pink pickles.

Never seen one, let alone five, so it should be interesting.

;-)

On Apr 10, 4:24 am, undbund <undb...@gmail.com> wrote:
> Hi i am trying to retrive data in chunks like 5 at a time or 10 at a
> time. Can anyone guide me to tutorials on how to go about doing this.
>
> Thanks

Lookup the LIMIT feature in the MySQL manual.
John

On Apr 10, 4:54 pm, John Andersen <j.andersen...@gmail.com> wrote:
> On Apr 10, 4:24 am, undbund <undb...@gmail.com> wrote:
>
> > Hi i am trying to retrive data in chunks like 5 at a time or 10 at a
> > time. Can anyone guide me to tutorials on how to go about doing this.
>
> > Thanks
>
> Lookup the LIMIT feature in the MySQL manual.
> John


I have found out how to do this using LIMIT.

Thanks for all your help.

Bye

John Andersen wrote:

> On Apr 10, 4:24 am, undbund <undb...@gmail.com> wrote:
>> Hi i am trying to retrive data in chunks like 5 at a time or 10 at a
>> time. Can anyone guide me to tutorials on how to go about doing this.
>>
>> Thanks
>
> Lookup the LIMIT feature in the MySQL manual.
> John

Does anyone know how LIMIT actually works in practice. I would assume that
the first read would return the first X records starting at record 1. When
the second read happens does the server physically start at X+1 and return
X records or does it actually re-read the first X records to get to the
starting point? And the third read? I guess what I'm getting at is MySQL
smart enough to remember where the last access finished (and if so, how) or
do we end up reading from the start of the table each time?

Does using LIMIT provide an indemnepotant view of the underlying table or
are we vulnerable to changes made in the underlying table between accesses?

Regards

On 10 Apr, 12:50, Gilbert <bugger....@no.spam.com> wrote:
> John Andersen wrote:
> > On Apr 10, 4:24 am, undbund <undb...@gmail.com> wrote:
> >> Hi i am trying to retrive data in chunks like 5 at a time or 10 at a
> >> time. Can anyone guide me to tutorials on how to go about doing this.
>
> >> Thanks
>
> > Lookup the LIMIT feature in the MySQL manual.
> > John
>
> Does anyone know how LIMIT actually works in practice. I would assume that
> the first read would return the first X records starting at record 1. When
> the second read happens does the server physically start at X+1 and return
> X records or does it actually re-read the first X records to get to the
> starting point? And the third read? I guess what I'm getting at is MySQL
> smart enough to remember where the last access finished (and if so, how) or
> do we end up reading from the start of the table each time?
>
> Does using LIMIT provide an indemnepotant view of the underlying table or
> are we vulnerable to changes made in the underlying table between accesses?
>
> Regards

More to the point, suppose you are doing a "LIMIT 0,10".

When you then do a "LIMIT 10,10", what happens if one of the original
first 10 records has now been deleted. Will you then jump over one of
the records that you didn't see in the first hit?

On Wed, 9 Apr 2008 21:18:05 -0700 (PDT), ThanksButNo wrote:
> On Apr 9, 9:05 pm, Michael Austin <maus...@firstdbasource.com> wrote:
>> undbund wrote:
>> > Hi i am trying to retrive data in chunks like 5 at a time or 10 at a
>> > time. Can anyone guide me to tutorials on how to go about doing this.
>>
>> > Thanks
>>
>> 5 pink pickles? 5 records? 5 columns? 5 words? 5 bytes?
>
> If it makes any difference, I vote for the pink pickles.
>
> Never seen one, let alone five, so it should be interesting.

They're usually made from ginger root. Quite tasty.

--
9. If a self-destruct mechanism is necessary, it will not be a large red button
labelled "Danger: Do Not Push". The big red button marked "Do Not Push" will
instead trigger a spray of bullets on anyone stupid enough to disregard it.
--Peter Anspach's list of things to do as an Evil Overlord

>> > Lookup the LIMIT feature in the MySQL manual.
>> > John
>>
>> Does anyone know how LIMIT actually works in practice. I would assume that
>> the first read would return the first X records starting at record 1. When
>> the second read happens does the server physically start at X+1 and return
>> X records or does it actually re-read the first X records to get to the
>> starting point? And the third read? I guess what I'm getting at is MySQL

It does need to read the records to the extent of figuring out whether
they are to be selected, or to sort them to determine order.
If the query cache can't be used, it needs to do this on each query.

>> smart enough to remember where the last access finished (and if so, how) or
>> do we end up reading from the start of the table each time?

MySQL is smart enough to NOT make the result of one query depend on
invisible variables set by previous queries. LIMIT is not a cursor.

>> Does using LIMIT provide an indemnepotant view of the underlying table or
>> are we vulnerable to changes made in the underlying table between accesses?

Can you get this by starting a transaction (using InnoDB tables)?

>> Regards
>
>More to the point, suppose you are doing a "LIMIT 0,10".
>
>When you then do a "LIMIT 10,10", what happens if one of the original
>first 10 records has now been deleted. Will you then jump over one of
>the records that you didn't see in the first hit?

LIMIT does not provide you with a cursor. It does not carry over context
from previous queries, except to the extent they modify the database.
If the database changes between your queries, so be it.

Gordon Burditt wrote:

>>> > Lookup the LIMIT feature in the MySQL manual.
>>> > John
>>>
>>> Does anyone know how LIMIT actually works in practice. I would assume
>>> that the first read would return the first X records starting at record
>>> 1. When the second read happens does the server physically start at X+1
>>> and return X records or does it actually re-read the first X records to
>>> get to the starting point? And the third read? I guess what I'm getting
>>> at is MySQL
>
> It does need to read the records to the extent of figuring out whether
> they are to be selected, or to sort them to determine order.
> If the query cache can't be used, it needs to do this on each query.
>
>>> smart enough to remember where the last access finished (and if so, how)
>>> or do we end up reading from the start of the table each time?
>
> MySQL is smart enough to NOT make the result of one query depend on
> invisible variables set by previous queries. LIMIT is not a cursor.
>

Thats what I suspected, which, in conjunction with the fact that the
database could change between requests, makes me wonder what you'd actually
use LIMIT for?

Regards