There are many columns of data in the table. The only column that I would
like to extract a value from is the password field (this is the key as
well). I do not have an AUTO_INCREMENT field. Although, I see how adding
that field could be of use by using it with the SELECT MAX() as you
mentioned.
The last record is whatever the last record was inserted using INSERT INTO.
To give you the overall picture of what I am trying to accomplish:
1) I am opening up a db table and searching for the password of the last
record in the table
2) I then open a flat file and search for that password and grab the next
record after that (as records are appended to the end of the flat file) and
any other subsequent records added to the flat file
3) Write those new records to the db table
In this scenario, the last record would be the last record from the flat
file added to the db table.
Another suggestion from [EMAIL PROTECTED] was to:
Select your password field, and whatever other fields you need to
Use
-mysql_num_rows() to capture the number of rows returned
-mysql_data_seek() to position pointer on last row (remember indexing
starts at 0)
-mysql_fetch_row() or mysql_fetch_array(), your choice, to return the
data.
This is done with one select statement, however all the passwords from the
table have to be loaded into array (perhaps not the most efficient way? But
better than what I had come up with.).
I do generally find that the more brief I am in describing an issue, the
more likely I am to get a reply. Then details can be given if needed, in
further correspondences.
I will give that AUTO_INCREMENT and SELECT MAX() a try as well.
Zach
-----Original Message-----
From: DL Neil [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, January 23, 2002 3:27 PM
To: Zach Curtis
Cc: [EMAIL PROTECTED]
Subject: Re: [PHP-DB] # of Records in Table
Zach,
We're going back and forth on this and getting no where...
So far all you have informed us is that the table has one column, which
contains a bunch of passwords (I also
suggest that this is not really the case and there'll at least be some sort
of userId field - but you haven't
bothered to tell me/us that)
The concept of "last" in relational terminology is ambiguous. Do you mean
last entered, or do you mean the row
with the field containing the highest value in the column - for example.
Some people are used to the idea that there is also some 'phantom' rowId
that counts/labels each row. In other
file systems this might have been the case, but the physically last record
in an RDBMS table-file may not
conform to either of the "last" definitions mentioned above. There is no
such 'highest' in an RDBMS unless you
put it there - as mentioned by another correspondent, it's a good idea to
use some sort of 'id' field in every
table. This can be generated for you with the AUTO_INCREMENT feature. With
appropriate design, eg first record
has id=1 and the succeeding records have id-s with ascending values, then
you can use SELECT MAX() against the
'id' or possibly against the AUTO_INCREMENT feature.
These commands are well documented - RTFM. Many tutorials with plenty of
examples of authentication techniques
exist on the PHP/MySQL web sites.
Next time, please don't be so (repeatedly) parsimonious in the provision of
information, if you expect/hope that
someone is going to give their (free) time to help you out. (grumble)
=dn
----- Original Message -----
From: "Zach Curtis" <[EMAIL PROTECTED]>
To: "DL Neil" <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: 23 January 2002 21:52
Subject: RE: [PHP-DB] # of Records in Table
> The key field is the password field, which is also the field that I would
> like to retrieve for that last record.
>
>
> Zach
>
> -----Original Message-----
> From: DL Neil [mailto:[EMAIL PROTECTED]]
> Sent: Wednesday, January 23, 2002 2:08 PM
> To: Zach Curtis
> Cc: [EMAIL PROTECTED]
> Subject: Re: [PHP-DB] # of Records in Table
>
>
> Zach,
>
> How can this "last record" be identified? Is there a key field or
something
> similar?
>
> Again: We might need to see the table definition to answer this.
>
> Please advise,
> =dn
>
>
> ----- Original Message -----
> From: "Zach Curtis" <[EMAIL PROTECTED]>
> To: "DL Neil" <[EMAIL PROTECTED]>
> Sent: 23 January 2002 20:49
> Subject: RE: [PHP-DB] # of Records in Table
>
>
> > The last record should be whatever the last record is in the table. For
> > example, if there are 1000 records in the table which COUNT(*) will tell
> me,
> > how can I get the password for record 1000. The only thing I can do that
> > would probably work is two query statements, one selecting COUNT(*) and
> the
> > other selecting "password". What I don't like about this method is that
I
> > would have to retrieve all of the passwords into an array, which I would
> > assume would be slow on larger tables. Ideally, I thought their would be
a
> > way to do this operation in one select statement. Any thoughts?
> >
> >
> > Zach
> >
> > -----Original Message-----
> > From: DL Neil [mailto:[EMAIL PROTECTED]]
> > Sent: Wednesday, January 23, 2002 1:11 PM
> > To: Zach Curtis; [EMAIL PROTECTED]
> > Subject: Re: [PHP-DB] # of Records in Table
> >
> >
> > Zach,
> >
> > > What syntax can I use to determine how many records are in a MySQL
table
> > and
> > > then retrieve the value of the field "password" for the last record? I
> > tried
> > > using some combinations of COUNT(*) and LIMIT with no success.
> >
> >
> > SELECT COUNT(*) will answer the first part. What did you try that lacked
> > success?
> >
> > How do you define "last record"? We might need to see the table
definition
> > to answer this.
> >
> > Regards,
> > =dn
> >
> >
> >
> >
> >
>
>
>
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