Re: quick mysql question

  • From: Alex Hall <mehgcap@xxxxxxx>
  • To: programmingblind@xxxxxxxxxxxxx
  • Date: Wed, 08 Apr 2009 07:47:17 -0400

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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