php - Compare data from two tables and check the same data -

hello have 2 tables in database.

the first 1 table disease above...

and second table patient ...

and have edit page want give user ability update his/her diseases. example below..

what want check disease column table patient column name table disease , check if data table patient same data table disease check checkboxes same disease.

i tried find way couldnt here code...

<?php $sql = "select name disease union select disease patient username='$username'"; $query_resource = mysql_query($sql);    while( $name = mysql_fetch_assoc($query_resource) ): ?>     <span><?php echo $name['name']; ?></span>     <input type="checkbox" name="disease[]" value="<?php echo $name['name']; ?>" /><br />   <?php endwhile; ?> 

the way store diseases in database this...

$disease = implode(",",$_post["disease"]); 

because user might have many diseases

my answer not looking however. if u building application should consider integrating relations between person , desies tables. besause it's mysql relational databases :)

if got right: not tested

<?php  $sql = "select disease patient username='$username'"; $query_resource = mysql_query($sql); $person = mysql_fetch_assoc($query_resource);  $persons_desisies = explode(',', $person['disease']);  $sql = "select name disease"; $query_resource = mysql_query($sql); $disease = array();    while( $name = mysql_fetch_assoc($query_resource) ):       ?>       <span><?php echo $name['name']; ?></span>       <input type="checkbox" name="disease[]" value="<?php echo $name['name']; ?>" <?php if(in_array($name['name'], $persons_desisies)): ?> checked="checked" <?php endif; ?>/><br />    <?php endwhile; ?> 

idea - getting patiens desieses list , checking full desies list. :)