如何从另一个表主键添加mysql外键？

Question

What should I add as the second value?

I tried last id, but it is not working.

I want to add the question's primary key.

$connect->exec(" INSERT INTO answers(choice_option, questions_id)
                 VALUES('$choiceoption', [what goes here?])");

Answer 1

Your code is a little bit old, maybe is Legacy code but I recommend to you that use mysql_insert_id() if primary key: questions_id is AUTO_INCREMENT. For example:

<?
  $connect->exec("INSERT INTO questions 
  (questions_points, questions_ask, answer_option, contest_id) 
  VALUES ('$questionspoints', '$questionsask', '$answeroption', '$lastid') ");
  //Get last inserted from question's table:
  $last_insert = mysql_insert_id();
  $connect->exec(" INSERT INTO answers(choice_option, questions_id)
  VALUES('$choiceoption', '$last_insert')");
 ?>

Suggestion: Use mysqli or PDO instead classic mysql because is deprecated.

More information: mysql_insert_id