Code execution order in for loop when mysql insert nodejs-CodePudding

I have a very simple question that I haven't been able to solve for days. I wrote the following simple code block to give an example.

var mysql = require("mysql")

var connection = mysql.createConnection({
  host: "localhost",
  user: "***",
  password: "***",
  database: "***",
  charset: "utf8mb4"
})

var testArr = ["banana", "apple", "orange", "strawberry"]

for (let fruit of testArr) {
    console.log("fruit check:"   fruit)

    var fruitName = connection.escape(fruit)

    var sql = "INSERT INTO test (name) VALUES ("   fruitName   ")";

    connection.query(sql, function (err, result) {
        if (err) throw err;
        console.log("1 record inserted");
    });
}

The only thing I want to do here is to actually proceed sequentially after entering the for loop. At the moment, the console side comes as follows;

fruit check:banana
fruit check:apple
fruit check:orange
fruit check:strawberry
1 record inserted
1 record inserted
1 record inserted
1 record inserted

I want it to come like this:

fruit check:banana
1 record inserted
fruit check:apple
1 record inserted
fruit check:orange
1 record inserted
fruit check:strawberry
1 record inserted

CodePudding user response：

Try to use promise when you connection your mysql,and use async/await.

you can get approximate answer here

CodePudding user response：

Try this approach with async - await and mysql2.
I changed the query to a prepared statement.

const mysql = require('mysql2/promise');

const loadData = async () => {
  try {
    var connection = await mysql.createConnection({
      host: 'localhost',
      user: '***',
      password: '***',
      database: '***',
      charset: 'utf8mb4',
    });

    var testArr = ['banana', 'apple', 'orange', 'strawberry'];

    for (let fruit of testArr) {
      console.log('fruit check:'   fruit);
      var sql = 'INSERT INTO test (name) VALUES (?)';
      await connection.execute(sql, [fruit])
      console.log('1 record inserted');
    }
  } catch (err) {
    throw err; // Or do something else with the error...
  }
};

loadData();