[SOLVED] Previous database ID

[studgate]

Hi Guys,

  is there a way to get the previous id of an object in

my database and other information related to the data in

that previous id??

For example if I have a customer name Jean and I want to

get the previous person information before Jean. if Jean

id is 5, I want to get name of person in 4 (previous id= id-1)

without knowing the id for jean(big database).

Please help.

Thanks in advance!

[cooldude832]

http://us.php.net/manual/en/function.mysql-insert-id.php

 

 

[Yesideez]

mysql_insert_id() will return the ID of the previously INSERTED id and I'm not sure it's suitable for this case.

 

I think you'll need to run a sELCT query on Jean to get her ID then subtract one - is that what you mean?

[studgate]

Yesideez, this is exactly what I want.

Please help,

Thank again.

[cooldude832]

mark it solved please

[studgate]

It is not solved!

 

How do I get the previous id for any data??

How do you get the previous id for the current ID??

Thanks again.

 

[Yesideez]

<?php
  $fetch=mysql_fetch_assoc(mysql_query("SELECT `id` FROM `table` WHERE `name`='Jean'"));
  $id=$fetch['id']
  $id--;
  echo 'ID before Jean is '.$id;
?>

 

That what you mean?

[studgate]

Thanks Yesideez but I was looking for something

more  like this

 

<?php
  $fetch=mysql_fetch_assoc(mysql_query("SELECT * FROM `table` WHERE id='currentid -1'"));
  $id=$fetch['id']
  $id--;
  echo 'ID before Jean is '.$id and the name from .$id is .$id[name];
?>

I hope you understand.

Thanks!

[Yesideez]

That isn't possible - you have to have a place in the table to reference as it doesn't behave like file access does.

 

With a file if you open it and read x bytes into it the pointer will stay at x bytes in.

[cooldude832]

this is because mysql tables are not so linear in their file construction, indexing optimizes the tables by moving more oftenly used data to easier accessed parts of the file (i.e beginning)

[studgate]

So there is no way to do something like this

 

 

$jean_id= X; previd=SELECT * FROM $wpdb->posts WHERE ID={$jean_id->ID} 

 

So I have to know the id  for Jean to get the previous

ID and the name???

[Yesideez]

As long as yuo have some information of Jean which is unique to the record then you can use that data to access Jean's record. Once you have that you can look at the ID and go back one to access the data.

 

SELECT `id`-1 FROM `table` WHERE `name`='Jean'

 

Think that'd work...

[studgate]

Thank everyone who replied.

I could not find a solution and

I want to put the topic as solved

to close it.

Thanks again.

[AndyB]

There's no guarantee that the record 'before' Jean's exists - it might well have been deleted in some other operation.

 

Do this as a two-step process.

 

SELECT id from tablename WHERE username = 'Jean'

abstract the value of id from the query result

 

SELECT * from tablename WHERE id<'$id' ORDER by id DESC LIMIT 1

abstract the data for the single record returned