If - Else

[Anon]

Hi i'm trying to get a text box to search a database for a match and if it finds a match then it goes to a specific page else it goes to another page. Heres the code:

<?
$db = mysql_connect ("localhost", "root", "orange");
mysql_select_db ("camco", $db);
$query = "SELECT aircraftreg FROM jobdetails";
$res = mysql_query ($query, $db);
$row = mysql_fetch_row ($res);

if ($aircraftreg == $row[2])

 {

header ("Location: history.php?aircraftreg=$aircraftreg");

 }

else
{
header ("Location: add_cust.php");
}
mysql_close ($db);
?>

I hope that someone can help. I works a bit what ever reg you put in it goes to add_cust.php but even when it's a reg thats on the database. Thanks

[Anon]

Your query isn't restricting the search to a particular row.
You need to say something like this:

$query = "SELECT aircraftreg FROM jobdetails where aircraftreg = $aircraftreg";
$res = mysql_query ($query, $db);

Then, since you are only asking for the same column you're matching on, you don't really need to retrieve the row--simply asking for the count of matching records will do:

if (! $res)
&nbsp;&nbsp;echo "query failed--programming error?";
elseif (mysql_num_rows($res) == 1)
&nbsp;&nbsp;header ("Location: history.php?aircraftreg=$aircraftreg");
else
&nbsp;&nbsp;header ("Location: add_cust.php");

Note that your original comparison:

if ($aircraftreg == $row[2])

could never work because you're comparing to the 3rd column
of the results, but you only ask for a single column so the only
element of $row that will have any data is $row[0].

[Anon]

Hi i've changed some of the code, but it's still not working properly. The aircraftreg can be any combination of letters and numbers. Heres my new code:

<?
$db = mysql_connect ("localhost", "root", "orange");
mysql_select_db ("camco", $db);
$query = "SELECT aircraftreg FROM aircraft WHERE regcode = $aircraftreg";
$res = mysql_query ($query, $db);

if ($res == $aircraftreg)
{
header ("Location: history.php?aircraftreg=$aircraftreg");
}

else
{
header ("Location: add_cust.php");
}

mysql_close ($db);
?>

hope you can help, thanks

[Anon]

mysql_query() doesn't give you the data directly, it returns an identifier that is used in further calls to mysql functions to return the actual data, see how many columns were returned/affected by your query, etc. $res in this case will just be a "magic identifier" for the mysql module and has no relationship to the actual value of the column 'aircraftreg' returned by the query. So comparing $reg and $aircraftreg will never be meaningful.

In the current case, you're not interested (as far as I can tell) with any actual data returned by the query, since the only column you ask for would have the same value as the where-condition key that the user already input. In other words, the question you're really asking is, Is this record present in my database? For this, just seeing if the query returned any rows or not is adequate; sorry if I didn't make that clear previously:

if (mysql_num_rows($res) == 1 )
&nbsp;&nbsp;&nbsp;header ("Location: history.php?aircraftreg=$aircraftreg");
else
&nbsp;&nbsp;&nbsp;header ("Location: add_cust.php");

[Anon]

Sorry for my lack of knowledge, i've only been using php for a month and I didn't pick up on what you were saying the first time, thanks for your help. I understand what you mean now, thanks Martin