RE: quick mysql question
- From: "Holdsworth, Lynn" <Lynn.Holdsworth@xxxxxxxxxxx>
- To: <programmingblind@xxxxxxxxxxxxx>
- Date: Wed, 8 Apr 2009 13:04:14 +0100
Hi Alex,
I don't think you need row numbers to accomplish paging.
I've written some PHP code below, which you'll need to tweak a bit.
If you can put the page number in the querystring:-
http://www.something.com/somepage.php?page=3
Then you can tweak the SQL statement with a limit clause:-
<?php
...
Extract($_GET); //exposes variables from the querystring
$recordsPerPage = 5; //Number of records on each page
//If page number not set, then set it to 1
If (!$page)
{
$page = 1;
}
//Calculate the first record you want to retrieve on this page
//Index is zero-based
$firstRecord = $recordsPerPage * ($page-1);
//Now build the SQL query with the limit clause
$query = "select <fieldNames>
From <tableName>
Where <whereClause>
Limit $firstRecord, $recordsPerPage";
...
?>
Let us know if this works for you.
Cheers, Lynn
Lynn Holdsworth
Web Analyst/Programmer - www.rnib.org.uk
-----Original Message-----
From: programmingblind-bounce@xxxxxxxxxxxxx
[mailto:programmingblind-bounce@xxxxxxxxxxxxx] On Behalf Of Alex Hall
Sent: 08 April 2009 12:47
To: programmingblind@xxxxxxxxxxxxx
Subject: Re: quick mysql question
Okay. How would I use this to control which records are displayed? Say
I have records 1-8, and the php page displays the first two, then the
next two, and so on, moving to the next two every time a "next" button
is clicked. How would the page know which two (or however many it was
set to display per page) to get? What if the user wants to go back? Does
this make sense?
Sorry if this comes out looking strange, I think my bn's ueb translator
is going crazy.
Have a great day,
Alex
> ----- Original Message -----
>From: "Octavian Rasnita" <orasnita@xxxxxxxxx
>To: <programmingblind@xxxxxxxxxxxxx
>Date sent: Wed, 8 Apr 2009 08:28:16 +0300
>Subject: Re: quick mysql question
>The indexes in a table are used for creating relations with the
records from
>other tables, and it would be a total mess if those indexes would
change.
>If you need to find how many records there are in a table, you
can simply
>count them using:
>select count(*) from table_name;
>Or you can put some conditions like:
>select count(*) from table_name where column1=123 and
another_column="abc"
>and another_one like '%bla%';
>--
>Octavian
>----- Original Message -----
>From: "Alex Hall" <mehgcap@xxxxxxx
>To: <programmingblind@xxxxxxxxxxxxx
>Sent: Wednesday, April 08, 2009 6:21 AM
>Subject: Re: quick mysql question
>> Okay, so the numbering is lost if you delete. Is there a more
robust way
>> of numbering, so that you would have gotten:
>> 1, abc'
>> 2, 'ghi'
>> 3, 'kno'
>> instead? I need the index of each record to always be sequential
so that I
>> can know how many total records there are and also know which
ones I have
>> used in the displaying of all of them.
>> Have a great day,
>> Alex
>>> ----- Original Message -----
>>>From: "R. Haynie" <rhaynie@xxxxxxxxxxx
>>>To: programmingblind@xxxxxxxxxxxxx
>>>Date sent: Tue, 07 Apr 2009 22:51:24 -0400
>>>Subject: Re: quick mysql question
>>>An example is worth a thousand words...
>>>create table tbl1 (fld1 INTEGER AUTO_INCREMENT,
>>>fld2 char(3),
>>>PRIMARY KEY (fld1));
>>>insert into tbl1 (fld2) values ('abc'), ('def'), ('ghi'),
>> ('jkl');
>>>select * from tbl1;
>>>-- gives you:
>>>1, 'abc'
>>>2, 'def'
>>>3, 'ghi'
>>>4, 'jkl'
>>>delete from tbl1 where fld1 in (2, 4);
>>>insert into tbl1 (fld2) values ('mno');
>>>select * from tbl1;
>>>-- gives you:
>>>1, 'abc'
>>>3, 'ghi'
>>>5, 'mno'
>>>HTH.
>>>-Rodney
>>>Alex Hall wrote:
>>>> Hi all,
>>>> If I have a table of records and one column is an autoincrement,
>> what
>>>> happens when I delete a record? I want to use the autoincrement
>> as an
>>>> index, so records 1, 2, 3, and 4 exist where 1-4 are the indexes
>> of
>>>> the records, If you delete record 3, do you then have records 1,
>> 2,
>>>> and 3, or 1, 2, and 4? If it is the second case, is there a
>> better way
>>>> to have an index of each record? I need to know how many
>> recordsI am
>>>> using on a page (it is sort of a photo viewer so I need to know
>> which
>>>> pictures are being shown and how many more there are) and how
>> many
>>>> total there are to go. Thanks.
>>>> Have a great day,
>>>> Alex
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