节点js插入mysql变量不起作用

Question

I am using MySql with node.js

i have this query and it works:

 connection.query('insert into username (name) values ("msg")', function(err,    rows, fields) {

    if(!err) {


     } });

it inserts the string "msg" , not the value of the variable msg , but when I want to insert the variable this does not work:

connection.query('insert into username (name) values '+ msg, function(err,    rows, fields) {

    if(!err) {


     } });

for example:

var msg = "hello world!";

Answer 1

You are missing the parenthesis and the quotes that make a valid insert statement in the second case. You are building a sql statement that looks like this:

'insert into username (name) values hello world'

which is malformed. Use the util module to make your string formatting easier:

var util - require('util');
var mySql = util.format('insert into username (name) values ("%s")', 'hello world');
connection.query(mySql, function(err,    rows, fields) {

if(!err) {


 } });

Answer 2

try this code

const connection = mysql.createConnection({
  host: 'localhost',
  user: 'root',
  password: 'pass',
  database: 'db_name'
});

connection.query(`INSERT INTO user_table (name, mail, pass) VALUES ('${user_name}', '${user_name}', '${user_name}');`, function (err, result, fields) {
  if (err) throw err;
  });