PHP Checkbox can not show checked on edit page -

there problem show checked in checkbox on edit page. there code below:

ssc<input type="checkbox"  name="ssc"class="form-control" value="ssc"  <?php if(isset($ssc)) echo ($data[6] == 'ssc') ? 'checked':''; ?>/>  hsc<input type="checkbox"  name="hsc" class="form-control" value="hsc"  <?php if(isset($hsc)) echo ($data[6] == 'hsc') ? 'checked':''; ?>/> 

okay, lets go throw issues

• mysql functions deprecated
• currently possible attacker can inject malicious sql because way pass variables
• beacuse $data variable contains education column
• the value of checkbox sent if checked otherwise it's not set
• the educatio column can contain 3 value , none of them equals data
  • ssc
  • ssc hsc
  • hsc

solutions:

• use mysqli functions instead mysql
• use prepared statements , parameterized queries.
• don't check if column set if defined select query
• always check if checkbox value sent isset or add hidden input same name , empty value above checkbox if box not checked value of hidden input sent
• check if string contains "words" (strpos($a, 'ssc') !== false - it's true when not false)

(and not use answer section give aditional data update question instead)