That makes a lot of sense. I have heard of limit 20, which will select the first 20 rows, but what is the comma? I guess I should say: what is the syntax of the limit clause? Thanks!
Have a great day, Alex
----- Original Message ----- From: "Holdsworth, Lynn" <Lynn.Holdsworth@xxxxxxxxxxx To: <programmingblind@xxxxxxxxxxxxx Date sent: Wed, 8 Apr 2009 13:04:14 +0100 Subject: RE: quick mysql question
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 therecords fromother tables, and it would be a total mess if those indexes wouldchange.
If you need to find how many records there are in a table, youcan simplycount them using:
select count(*) from table_name;
Or you can put some conditions like:
select count(*) from table_name where column1=123 andanother_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 morerobust wayof numbering, so that you would have gotten: 1, abc' 2, 'ghi' 3, 'kno' instead? I need the index of each record to always be sequentialso that Ican know how many total records there are and also know whichones I haveused 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,whathappens when I delete a record? I want to use the autoincrementas anindex, so records 1, 2, 3, and 4 exist where 1-4 are the indexesofthe 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 abetter wayto have an index of each record? I need to know how manyrecordsI amusing on a page (it is sort of a photo viewer so I need to knowwhichpictures are being shown and how many more there are) and howmanytotal there are to go. Thanks.
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