| Re: isset not working with select [message #181345 is a reply to message #181342] |
Mon, 13 May 2013 12:49   |
Scott Johnson
Messages: 196
Registered: January 2012
Karma:
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Senior Member |
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On 5/13/2013 4:01 AM, richard wrote:
> http://mroldies.net/showtable.php?year=1960
>
>
>
> $result = mysql_query("SELECT acover,bcover FROM A$year WHERE id =
> $number");
> if (!$result) { echo 'Could not run query: ' . mysql_error(); exit; }
> $cov = mysql_fetch_row($result);
>
>
> if (isset($cov[0]))
> {echo "<img src='http://mroldies.net/covers/$year/".$cov[0]."'>";}
> echo "<img src='http://mroldies.net/covers/$year/".$cov[1]."'>";
>
> On item #1 in the table, the panel appears with the desired images as
> wanted.
> On item #2 image place holders appear because I do not have them online
> yet.
> I do not want to see the place holders if there is not an image.
> What to use to do that?
>
> Also, if you click on 1961, or any other year, and then any item in the
> table, you will get a message below the videos stating the column does not
> exist so it can't continue processing.
> How can I bypass this when that database does not have that column?
>
First off you should stop using the mysql extensions and start using a
PDO or MySQLi. (read up on the extensions to find out why, specifically
mysql_fetch_row)
2. Is your query indeed returning cov[1]. Have you done any debugging
techniques to determine the variables contents.
C. Your display logic is not very sound. The second row will ALWAYS try
to display regardless of cov[0] and whether or not cov[1] is set.
In fact you must have error 'notices' suppressed or you would of gotten
an undefined index for the second row cov[1] and may have given you an
idea why it is not working. When developing have all your errors tuned
on. I won't repeat how since it has been explained many times prior.
Here is some homework.
* Begin updating your code to use mysqli or your pdo.
* Learn some debugging techniques such as var_export, print_f, echo....
* Turn ALL your errors on
The first one will prevent your scripts from shutting down once the
mysql extensions are turned off on future PHP releases.
The last 2 will go a long way in you finding many issues that you will
have in the future on your own.
Good luck.
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