将 mysql 查询行存储在变量中以供以后在另一个 mysql 查询中使用

问题描述

我有 2 个不同的表，其中第一个表用于检索要存储在第二个表中的数据，例如，如果第一个表中有 3 个项目，我将运行 for 循环 3 次以检索信息并将其逐行存储在第二个表中，我还必须为第二个表的主键使用唯一 ID，因此我必须运行另一个 MysqL 查询以检索第二个表中的所有 ID 并将 1 添加到id 生成新 ID，但对我来说问题是当我尝试将 connection.query 放入另一个 connection.query 时，外部 connection.query 在运行内部 connection.query 之前运行 3 次，因此项目不会被存储并且 id 没有更新，给我一个重复的主键错误，我尝试使用函数但它没有帮助，这里是

app.get('/submit-check',function (request,response) {
  function insert(sql2) {
    connection.query(sql2,function (err,result1) {
      if (err) throw err;
    });
  }
  function other(value,index) {
    let sql = "SELECT * FROM ORDERS"
    connection.query(sql,results) {
      var id;
      if (results.length == 0) {
        id = 0
      } else {
        id = results[results.length - 1].orderID;
      }
      // for (let j = 0; j < results.length; j++) {
      //   list.push(results[j].orderID)
      // }
      // if (list.length == 0) {
      //   id = 0
      // }
      // else {
      //   var largest = 0;
      //   for (let i = 0; i <= list.length; i++) {
      //     if (parseInt(list[i]) > largest) {
      //       var largest = parseInt(list[i]);
      //     }
      //   }
      //   id = largest + 1
      // }
      id = id + 1;
      var add = request.query.state + " " + request.query.address + " " + request.query.Unumber + " " + request.query.zip
      var custID = value[index].custID
      var bookID = value[index].bookID
      var Email = request.query.email
      var CardName = request.query.cardname
      var CardNumber = request.query.cardnumber
      var ExDate = request.query.expmonth + "/" + request.query.expyear
      var CVV = request.query.cvv
      var qty = 1
      var sql2 = "INSERT INTO orders (orderID,custID,bookID,QTY,CardName,CardNumber,ExDate,CVV,Email,Address,createdAt,updatedAt) VALUES('" + id + "','" + custID + "','" + bookID + "','" + qty + "','" + CardName + "','" + CardNumber + "','" + ExDate + "','" + CVV + "','" + Email + "','" + add + "',CURDATE(),CURDATE() )"
      insert(sql2)
    })
  }
  function setValue(value) {
    for (let index = 0; index < value.length; index++) {
      other(value,index)
    }
  }
  let sql3 = "SELECT * FROM carts"
  var cart_db;
  connection.query(sql3,result) {
    cart_db = result
    setValue(cart_db)
  })
  // console.log(cart_db)
  response.render("aftercheck",{ attributes: request.query,cardno: "****-****-****" + request.query.cardnumber.slice(-5,) });
})

先谢谢你

解决方法

您的代码有很多很多问题。我在这个基于等待/异步的重写中添加了 TODO 注释，您可能需要在其中修复一些问题。由于没有您的数据库，我自然无法对此进行测试。

async function queryP(connection,sql,parameters = undefined) {
  return new Promise((resolve,reject) => {
    connection.query(sql,parameters,function (err,results) {
      if (err) return reject(err);
      resolve(results);
    });
  });
}

app.get("/submit-check",async function (request,response) {
  // TODO: these need to be validated
  const {
    address,Unumber,zip,expyear,state,expmonth,email: Email,cardname: CardName,cardnumber: CardNumber,cvv: CVV,} = request.query;
  const add = `${state} ${address} ${Unumber} ${zip}`;
  const ExDate = `${expmonth}/${expyear}`;

  const cartData = await queryP(connection,"SELECT * FROM carts"); // TODO: this is not safe with multiple customers
  const [maxOrderIdRow] = await queryP(connection,"SELECT MAX(id) as maxid FROM orders");
  const orderId = (maxOrderIdRow.maxid || 0) + 1; // TODO: this is not safe in the face of concurrent requests
  // Using a for loop rather than .map and await and so on is simpler here
  for (let i = 0; i < cartData.length; i++) {
    const cartRow = cartData[i];
    const custID = cartRow.custID;
    const bookID = cartRow.bookID;
    const qty = 1;
    // TODO: rethink how credit cards are saved – we can't save them in the database like this or we'll be out of business
    await queryP(
      connection,`INSERT INTO orders (orderID,custID,bookID,QTY,CardName,CardNumber,ExDate,CVV,Email,Address,createdAt,updatedAt) VALUES(?,?,CURDATE(),CURDATE() )`,[orderId,qty,add],);
  }

  response.render("aftercheck",{
    attributes: request.query,cardno: "****-****-****" + CardNumber.slice(-5),});
});