php - 将数组放置在PHP中的WHERE-子句中，而不需要击中X次Postgres

如果不在PHP/PostgreSQL中创建50个pg_execute-命令，如何将数组放到下面的WHERE-子句中？

     // to get the question_ids of the newest questions
     $result_q_id = pg_prepare($dbconn, "query6", "SELECT question_id
         FROM questions
         ORDER BY was_sent_at_time
         DESC LIMIT 50;"
     );
     $result_question_id = pg_execute($dbconn, "query6", array());

     // to get all question ids
     $question_ids = pg_fetch_all($result_question_id);

     // to get titles, question_id from the db by using the question ids
     $result = pg_prepare($dbconn, "query8", "SELECT title
         FROM questions
         WHERE question_id = $1            // Problem here! How to get many WHERE's?
         ORDER BY was_sent_at_time
         DESC LIMIT 50;"
     );
     $result = pg_execute($dbconn, "query8", array($question_ids));
            // Problem here, since it is an array

对于第一次出现文本Problem here的行，我得到以下错误。

Warning: pg_execute() [function.pg-execute]: Query failed: ERROR: invalid input syntax for integer: "Array" in /var/www/codes/handlers/handle_questions_by_time.php on line 22
Call Stack

最佳答案

子查询解决了所有这些问题。。。

     $result = pg_prepare($dbconn, "query8",
"SELECT title
FROM questions
WHERE question_id in (SELECT question_id
           FROM questions
           ORDER BY was_sent_at_time
           DESC LIMIT 50)
ORDER BY was_sent_at_time
DESC LIMIT 50;"