Checking checkboxes from database values - php

Question

I post values from check boxes into a database for a user profile. When the user goes to edit his/her profile I want the checkboxes that they selected previously to be checked so they don't lose that info after updating their profile. I have tried many different solutions but with no luck.
The check box values get entered into table name members_teachers into a column called focus and are seperated by a comma for example art,mathematics,dance etc I am not sure how close or far I am away at accomplishing my goal but I greatly appreicate any help or suggestions you can provide. Thank you very much in advance
My code to try and check the values is
<?php
$focusQuery = mysql_query("SELECT focus FROM members_teachers WHERE id = $member_id") or die;
while ($new_row = mysql_fetch_assoc($focusQuery)){
$focusRow = $row['focus'];
$focusValue = explode(',', $focusRow);
foreach($focusValue as $newFocus){
//echo $newFocus;
//echo "<br/>";
$result = mysql_query("SELECT focus FROM members_teachers WHERE focus LIKE '%$focusRow%'") or die;
if(mysql_num_rows($result) > $newFocus){
$checked = 'checked="checked"';
}
else{
$checked = '';
}
}
}
?>
This is my html
<label for="art-focus">Art</label>
<input name="focus[]" type="checkbox" value="Art" <?php echo $checked ?>>
<label for="math-focus">Mathematics</label>
<input name="focus[]" type="checkbox" value="Mathematics" <?php echo $checked ?>>
<label for="dance-focus">Dance</label>
<input name="focus[]" type="checkbox" value="Dance" <?php echo $checked ?>>

Answer 1

<?php
// Create connection
$con=mysqli_connect("hostname","username","pass","dbname");
// Check connection
if (mysqli_connect_errno($con))
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$result = mysqli_query($con,"SELECT focus FROM members_teachers WHERE id = $member_id");
while($row = mysqli_fetch_array($result))
{
$focus=explode(",",$row['focus']);
?>
<input type="checkbox" name="focus[]" value="Art" <?php if(in_array("Art",$focus)) { ?> checked="checked" <?php } ?> >
<input type="checkbox" name="focus[]" value="Mathematics" <?php if(in_array("Mathematics",$focus)) { ?> checked="checked" <?php } ?> >
<input type="checkbox" name="focus[]" value="Dance" <?php if(in_array("Dance",$focus)) { ?> checked="checked" <?php } ?> >
<?php
}
?>

Answer 2

<?php
$focusedValues = array();
$focusQuery = mysql_query("SELECT focus FROM members_teachers WHERE id = $member_id") or die;
while ($row = mysql_fetch_assoc($focusQuery)){
$focusedValues = explode(',', $row['focus']);
}
?>
<label for="art-focus">Art</label>
<input name="focus[]" type="checkbox" value="Art" <?php echo in_array('Art', $checked) ?>>
<label for="math-focus">Mathematics</label>
<input name="focus[]" type="checkbox" value="Mathematics" <?php echo in_array('Mathematics', $checked) ?>
<label for="dance-focus">Dance</label>
<input name="focus[]" type="checkbox" value="Dance" <?php echo in_array('Dance', $checked) ?>
I don't know why you were SELECTing for the second time, that's pointless, you already know what's checked because it's in $focusedValues. Also, in your code, $checked would be empty if nothing was checked and checked="checked" otherwise. You obviously need a variable for each input, no?

Answer 3

<?php $hobby = $row['hobbies'];
$hobbies = explode (' ', $hobby);
?>
<input type="checkbox" name="hobbies[]" value="cricket" <?php echo in_array('cricket', $hobbies?'checked':'') ?> >cricket
<input type="checkbox" name="hobbies[]" value="singing" <?php echo in_array('singing' , $hobbies ?'checked': '') ; ?> >singing
<input type="checkbox" name="hobbies[]" value="football" <?php echo in_array('football', $hobbies ?'checked': '') ; ?> >footballl