从SELECT查询的'IN（...）'内的数组返回数据

I have the following query:

SELECT question_code FROM table_questions WHERE question_code IN (1,2,3,111,222);

Here, values (1,2,3,111,222) are coming from PHP array.

The output for the above query is:

question_code
      1
      2
      3

I want the output to be the question_codes which are not in the table and present in the Array.

i.e. I want the output to be question_code which do not exist in the table.

question_code
    111
    222

I know this problem can be handled in PHP after retrieving the data from the Table. But as I may have large number of tuples, solution which can take care of this thing at query level would be helpful.

You will get the record of SELECT question_code FROM table_questions WHERE question_code IN (1,2,3,111,222); in array and values (1,2,3,111,222) are coming from PHP array.

Use array_diff to compare two arrays and gets the difference. For reference http://www.w3schools.com/php/func_array_diff.asp

If you want to use plain SQL you have to use a LEFT JOIN:

SELECT c.question_code
FROM (SELECT 1 AS question_code
      UNION ALL select 2
      UNION ALL SELECT 3
      UNION ALL SELECT 111
      UNION ALL SELECT 222) AS c
  LEFT JOIN table_questions q
  ON c.question_code = q.question_code
WHERE
  q.question_code IS NULL

you can create the subquery SELECT .. UNION ALL .. dynamically, like this:

<?php
  $ids = array(1,2,3);
  $subquery  = str_repeat('SELECT ? AS q UNION ALL ', count($ids) - 1) . 'SELECT ? AS q';
  $sql = <<<SQL
    SELECT c.q FROM ($subquery) AS c
      LEFT JOIN table_questions q
      ON c.q = q.question_code
    WHERE
      q.question_code IS NULL
  SQL;
  $stm = $db->prepare($sql);
  $stm->execute($ids);
  $data = $stm->fetchAll();
?>

but it might not be too pratical... the only alternative is to process the returned question_codes codes in php.