Edit form nulliifes any data which is not altered

[theboyholty]

I've got a form which is for editing purposes, its shown below. The form fills up with the data for editing and any fields the user changes are successfully changed, but any fields which are NOT altered by the user, are tyhen set to NULL (or no data). Is there anything I can do to retain previously stored data?

 

The form is shown below.

 

<form action="<?php $_SERVER['PHP_SELF']; ?>" method="POST">

<table border="1"><tr><td colspan="2">EDIT RESULT DETAILS</td></tr>

<tr><td>MatchID</td><td> <input name="MatchIDedit" value="<?php echo $showdata['MatchID']; ?>" size="5"></td></tr>

<tr><td>MatchTypeID</td><td> <input name="MatchTypeID" value="<?php echo $showdata['MatchTypeID']; ?>" size="5"></td></tr>

<tr><td>SeasonID</td><td> <input name="SeasonID" value="<?php echo $showdata['SeasonID']; ?>" size="5"></td></tr>

<tr><td>MatchNum</td><td> <input name="MatchNum" value="<?php echo $showdata['MatchNum']; ?>" size="5"></td></tr>

<tr><td>TeamID</td><td> <input name="TeamID" value="<?php echo $showdata['TeamID']; ?>" size="5"></td></tr>

<tr><td>Date</td><td> <input name="Date" value="<?php echo $showdata['Date']; ?>" size="15"></td></tr>

<tr><td>Venue</td><td> <input name="Venue" value="<?php echo $showdata['Venue']; ?>" size="6"></td></tr>

<tr><td>HT</td><td> <input name="HTGlsSc" value="<?php echo $showdata['HTGlsSc']; ?>" size="2">

<input name="HTGlsConc" value="<?php echo $showdata['HTGlsConc']; ?>" size="2"></td></tr>

<tr><td>FT</td><td> <input name="FTGlsSc" value="<?php echo $showdata['FTGlsSc']; ?>" size="2">

<input name="FTGlsConc" value="<?php echo $showdata['FTGlsConc']; ?>" size="2"></td></tr>

<tr><td>Result</td><td> <input name="WDL" value="<?php echo $showdata['WDL']; ?>" size="5"></td></tr>

<tr><td>Points</td><td> <input name="Points" value="<?php echo $showdata['Points']; ?>" size="3"></td></tr>

<tr><td>LgePos</td><td> <input name="LgePos" value="<?php echo $showdata['LgePos']; ?>" size="3"></td></tr>

<tr><td>Scorers</td><td> <input name="Scorers" value="<?php echo $showdata['Scorers']; ?>" size="100"></td></tr>

<tr><td>Attendance</td><td><input name="Attendance" value="<?php echo $showdata['Attendance']; ?>" size="8"></td></tr>

 

<tr><td colspan="2"><input type="submit" name="submit" value="Submit" /></td></tr>

</table>

</form>

Thanks for your help.

[JonnoTheDev]

Build your SQL query up on only fields that contain data:

i.e.

$sql = array();
if(strlen(trim($_POST['name))) {
$sql[] = "name='".$_POST['name']."'";
}
if(strlen(trim($_POST['address))) {
$sql[] = "address='".$_POST['address']."'";
}

if(count($sql)) {
$setPart = implode($sql, ",");
mysql_query("UPDATE tableName SET ".$setPart." WHERE id='".$_POST['id']."'");
}