javascript node.js从sql query中设置一个变量来计算表中的行数。

const mysql = require('mysql');

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

connection.connect((err) => {
  if (err) throw err;
  console.log('Connected to the database');
});

const query = 'SELECT COUNT(*) AS row_count FROM your_table';
connection.query(query, (err, results) => {
  if (err) throw err;
  const rowCount = results[0].row_count;
  console.log('Number of rows:', rowCount);
});

connection.end((err) => {
  if (err) throw err;
  console.log('Disconnected from the database');
});