code working after clicking button twice - php

Question

I am using following code to delete multiple vlues from database, but some how i have to click the delete button twice to delete the values, Please look through the following code and suggest me how to delete values with single click
<?php
include("connection.php");
$sql="SELECT * FROM deptag";
$result=mysql_query($sql);
$count=mysql_num_rows($result);
if (isset($_POST['delete']))
{
if (isset($_POST['checkbox']))
{
$checkbox = $_POST['checkbox'];
if (is_array($checkbox)) {
foreach ($checkbox as $key => $id)
{
mysql_query("DELETE FROM deptag WHERE id=".$id);
}
}
}
}
?>
<table width="400" border="0" cellspacing="1" cellpadding="0">
<tr>
<td><form name="form1" method="post" action="">
<table width="400" border="0" cellpadding="3" cellspacing="1" bgcolor="#CCCCCC">
<tr>
<td bgcolor="#FFFFFF"> </td>
<td colspan="4" bgcolor="#FFFFFF"><strong>Delete multiple rows in mysql</strong> </td>
</tr>
<tr>
<td align="center" bgcolor="#FFFFFF">#</td>
<td align="center" bgcolor="#FFFFFF"><strong>Tag</strong></td>
</tr>
<?php
while($rows=mysql_fetch_array($result)){
?>
<tr>
<td align="center" bgcolor="#FFFFFF"><input name='checkbox[]' type='checkbox' id='checkbox' value="<?php echo $rows['id']; ?>"></td>
<td bgcolor="#FFFFFF"><?php echo $rows['tagdep']; ?></td>
</tr>
<?php
}
?>
<tr>
<td colspan="5" align="center" bgcolor="#FFFFFF"><input name="delete" type="submit" id="delete" value="Delete"></td>
</tr>
</table>
</form>
</td>
</tr>
</table>

Answer 1

I'll convert first your MySQL to MySQLi:
connection.php:
<?php
$con=mysqli_connect("localhost","YourUsername","YourPassword","YourDatabase");
if(mysqli_connect_errno()){
echo "Error".mysqli_connect_error();
}
?>
YOUR DELETE FILE:
<?php
include("connection.php");
if (isset($_POST['delete']))
{
$counter=$_POST['hiddencounter'];
$checkbox=$_POST['checkbox'];
for($x=0;$x<=$counter;$x++){
if(empty($checkbox[$x])){
/* DO NOTHING */
}
else {
mysqli_query($con,"DELETE FROM deptag WHERE id='checkbox[$x]'");
}
} /* END OF FOR LOOP */
} /* END OF IF ISSET DELETE */
$result=mysqli_query($con,"SELECT * FROM deptag");
$count=mysqli_num_rows($result);
?>
<table width="400" border="0" cellspacing="1" cellpadding="0">
<tr>
<td><form name="form1" method="post" action="">
<table width="400" border="0" cellpadding="3" cellspacing="1" bgcolor="#CCCCCC">
<tr>
<td bgcolor="#FFFFFF"> </td>
<td colspan="4" bgcolor="#FFFFFF"><strong>Delete multiple rows in mysql</strong> </td>
</tr>
<tr>
<td align="center" bgcolor="#FFFFFF">#</td>
<td align="center" bgcolor="#FFFFFF"><strong>Tag</strong></td>
</tr>
<?php
$counter=0; /* LET US SET A COUNTER */
while($rows=mysqli_fetch_array($result)){
$id=$rows['id'];
?>
<tr>
<td align="center" bgcolor="#FFFFFF"><?php echo "<input name='checkbox[$counter]' type='checkbox' id='checkbox' value='$id'>"; ?></td>
<td bgcolor="#FFFFFF"><?php echo $rows['tagdep']; ?></td>
</tr>
<?php
$counter=$counter+1; /* INCREMENT COUNTER EVERY LOOP */
} /* END OF WHILE LOOP */
echo "<input type='hidden' name='hiddencounter' value='$counter'>"; /* PUT THE OVERALL COUNTER INTO A HIDDEN FIELD */
?>
<tr>
<td colspan="5" align="center" bgcolor="#FFFFFF"><input name="delete" type="submit" id="delete" value="Delete"></td>
</tr>
</table>
</form>
</td>
</tr>
</table>

Answer 2

just move your select query below delete code or use this
<?php
include("connection.php");
if (isset($_POST['delete']))
{
if (isset($_POST['checkbox']))
{
$checkbox = $_POST['checkbox'];
if (is_array($checkbox)) {
foreach ($checkbox as $key => $id)
{
mysql_query("DELETE FROM deptag WHERE id=".$id);
}
}
}
}
$sql="SELECT * FROM deptag";
$result=mysql_query($sql);
$count=mysql_num_rows($result);
?>

Answer 3

You need to move the following code to immediately after the include("connection.php"); line
if(isset($_POST['delete']))
{
if(isset($_POST['checkbox']))
{
$checkbox = $_POST['checkbox'];
if (is_array($checkbox)) {
foreach ($checkbox as $key => $id)
{
mysql_query("DELETE FROM deptag WHERE id=".$id);
}
}
}
}
After this place the code
$sql="SELECT * FROM deptag";
$result=mysql_query($sql);
$count=mysql_num_rows($result);
Note: mysql_* functions are deprecated, so that, use mysqli_* or PDO

Answer 4

You have to rearrange you code so that it will fetch data from db after the delete
if (isset($_POST['delete']))
{
if (isset($_POST['checkbox']))
{
$checkbox = $_POST['checkbox'];
if (is_array($checkbox)) {
foreach ($checkbox as $key => $id)
{
mysql_query("DELETE FROM deptag WHERE id=".$id);
}
}
}
}
$sql="SELECT * FROM deptag";
$result=mysql_query($sql);
$count=mysql_num_rows($result);
PS : Please consider sql injection vulnerability
How can I prevent SQL injection in PHP?