mysql - 在 mysql for nodejs 的 where 子句中使用变量与硬编码

Question

我正在为 nodejs 使用 npm mysql 驱动程序。如何在查询的 where 子句中使用变量？

//-----这样不行，这里我是在where子句中使用变量。------

app.get('/query1', function (req, res) {    
  var seat_id = req.query.seat_id

connection.query('SELECT * FROM seatpic where seatsid = "seat_id" ',function(err,rows,fields){
  if(err){
    console.log('There is an error in the query!');
  }else {
    console.log("value of var seat_id is:" ,seat_id);
        console.log('Data received from Db:\n');
        console.log(rows);
}

        res.json (rows)

});

});


//-----This works. Hardcoding the where clause with a number.---------


app.get('/query1', function (req, res) {    
  var seat_id = req.query.seat_id

connection.query('SELECT * FROM seatpic where seatsid = 6 ',function(err,rows,fields){
  if(err){
    console.log('There is an error in the query!');
  }else {
    console.log("value of var seat_id is:" ,seat_id);
        console.log('Data received from Db:\n');
        console.log(rows);
}

        res.json (rows)

});

});

Answer 1

您可以在查询中使用 ? 并将值作为数组提供，如下所示

connection.query("SELECT * FROM seatpic where seatsid = ?", [seatid], function(err,rows,fields){...

其中 [seatid] 是一个包含您的动态值的数组。

有关更多信息，请参见以下内容 - https://www.npmjs.com/package/mysql#performing-queries