Actually, if I had spent more time thinking about it, I could have come up with
an example less contrived than the alias, 'aaaa'. Let's say the first entry in
the table is the alias, 'williamson.' Based on the current query, there can be
no:
'williams'
'william'
'willi'
'will'
My previously stated assumptions still apply. Of course, if the first entry is
'will,' there could be a 'willi,' etc.
Regards,
Dave
-----Original Message-----
From: Mitchell, David
Sent: Sun 10/2/2005 11:11 AM
To: php-db@lists.php.net
Cc:
Subject: RE: [PHP-DB] If syntax
Please PMJI, but I'm new to PHP but have a little experience with
databases, and I have a question:
Is there a particular reason that LIKE is used in the query? Let's say
you had the contrived alias value in the table, 'aaaaa', and one wanted to add
the alias, 'aaaa' (or fewer 'a's). Wouldn't the query misreport that the
alias, 'aaaa', already exists?
I'm assuming that the number of characters in the alias can vary by
some range (e.g., 3 to 10 characters), and that:
"SELECT alias FROM tablename WHERE alias LIKE '$alias%' LIMIT 1";
becomes:
"SELECT alias FROM tablename WHERE alias LIKE 'aaaa%' LIMIT 1";
at execution-time.
Regards,
Dave
-----Original Message-----
From: Jeffrey [mailto:[EMAIL PROTECTED]
Sent: Sun 10/2/2005 3:32 AM
To:
Cc: PHP DB
Subject: Re: [PHP-DB] If syntax
See below...
Ron Piggott wrote:
>Take a look at my if ( ) syntax line below. I am wondering if
I have it
>wrong in same way. What I am trying to achieve is if the
alias the user
>enters is already found in the database I want the words
"Alias already in
>use" to be shown on the screen; otherwise "Unique alias" to be
shown on the
>screen.
>
>PRESENTLY alias already in use is what comes up all the time.
>
>Ron
>
>
>mysql_connect(localhost,$username,$password);
>@mysql_select_db($database) or die( "Unable to select
database");
>$query="SELECT * FROM tablename WHERE alias LIKE '$alias%'";
>
>if (mysql_query($query))
>
>{
>
>echo "Alias already in use";
>
>} else {
>
>echo "Unique alias";
>
>mysql_close();
>
>}
>
>
>
Whether or not there are any matches, you will always have a
database
query - hence mysql_query($query) will always produce something
Instead you need to see if there are any matches to your
variable.
Also, "SELECT * FROM [some_table] is tremendously inefficient
when you
only need to count results. You are basically calling up every
result in
your entire table just to see if a single column entry matches
a variable.
I would suggest something like..
mysql_connect(localhost,$username,$password);
@mysql_select_db($database) or die( "Unable to select
database");
$query="SELECT alias FROM tablename WHERE alias LIKE '$alias%'
LIMIT 1";
$result=(mysql_query($query))
if (mysql_num_rows($result)==1)
{
echo "Alias already in use";
} else {
echo "Unique alias";
mysql_close();
}
Good luck,
Jeffrey
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