javascript - MySQL 循环查询 Javascript 不起作用

Question

我在这个循环中使用了闭包。但它只在控制台日志上打印正确的数据，并且sql查询不起作用。 MySQL上插入的数据是循环的最后一个变量。我认为这是因为MySQL的写入速度。但不知道如何解决。任何想法？谢谢

  module.exports = function (callback) {
  queryGetForSend = "SELECT * FROM image WHERE send_request is NULL AND post_request is NOT NULL AND year(moderate_time) = year(curdate()) AND month(moderate_time) = month(curdate()) AND (time(moderate_time) < (curtime() - 15));";
  conn.query(queryGetForSend, function(err, rows, fields){
    for (i in rows) {
      if (rows[i].post_request == 'approve') {
        resultSend = 1
      } else {
        resultSend = 2
      }
      var fileID = rows[i].img_md5;
      queryString = fileID + "=" + resultSend;

      //  Request url:  "http://im-api1.webpurify.com/image_queue/results/?key="
      var d = new Date();
      Date.masks.default = 'YYYY-MM-DD hh:mm:ss';
      sendTime = d.format();

      (function(queryString, sendTime) {
        querySent = "UPDATE image SET send_request=1,result_sent='"+queryString+"',send_time='"+sendTime+"' WHERE send_request is NULL AND post_request is NOT NULL AND year(moderate_time) = year(curdate()) AND month(moderate_time) = month(curdate()) AND (time(moderate_time) < (curtime() - 15));";
        conn.query(querySent, function (err, rows, fields) {
          if (err) throw err;
          console.log("http://google.com?key=" + key + "&" + queryString);
        });
      })(queryString, sendTime);

      (function(queryString){
        request.get("http://google.com" + key + "&" + queryString, function(err, res, body) {
        });
      })(queryString);
    }
//    callback(rows);
  });
};

Answer 1

两个建议:

• 避免在 SQL 查询中串联，而是使用占位符或准备好的语句(如果您关心安全性)。

• 使用array.forEach()代替带有闭包的常规for循环，以避免意外使用for循环内设置的变量:

  conn.query(queryGetForSend, function(err, rows, fields) {
    if (err) throw err;
    rows.forEach(function(row) {
      var resultSend;
      if (row.post_request == 'approve') {
        resultSend = 1
      } else {
        resultSend = 2
      }
      var fileID = row.img_md5;
      var queryString = fileID + '=' + resultSend;
  
      var d = new Date();
      Date.masks.default = 'YYYY-MM-DD hh:mm:ss';
      var sendTime = d.format();
  
      var querySent = 'UPDATE image SET send_request=1, result_sent=?, send_time=? WHERE send_request IS NULL AND post_request IS NOT NULL AND year(moderate_time) = year(curdate()) AND month(moderate_time) = month(curdate()) AND (time(moderate_time) < (curtime() - 15));';
      conn.query(querySent, [queryString, sendTime], function (err) {
        if (err) throw err;
        console.log('http://google.com?key=' + key + '&' + queryString);
      });
  
      request.get('http://google.com?key=' + key + '&' + queryString, function(err, res, body) {
      });
    });
  });