Jassif Team Institution

let mysql = require('mysql');

let con = mysql.createConnection({
  host: "localhost",
  user: "yourusername",
  password: "yourpassword",
  database: "mydb"
});

con.connect(function(err) {
  if (err) throw err;
  con.query("SELECT * FROM customers", function (err, result, fields) {
    if (err) throw err;
    console.log(result);
  });
});

C:\Users\Your Name>node demo_db_select.js

[
  { id: 1, name: 'John', address: 'Highway 71'},
  { id: 2, name: 'Peter', address: 'Lowstreet 4'},
  { id: 3, name: 'Amy', address: 'Apple st 652'},
  { id: 4, name: 'Hannah', address: 'Mountain 21'},
  { id: 5, name: 'Michael', address: 'Valley 345'},
  { id: 6, name: 'Sandy', address: 'Ocean blvd 2'},
  { id: 7, name: 'Betty', address: 'Green Grass 1'},
  { id: 8, name: 'Richard', address: 'Sky st 331'},
  { id: 9, name: 'Susan', address: 'One way 98'},
  { id: 10, name: 'Vicky', address: 'Yellow Garden 2'},
  { id: 11, name: 'Ben', address: 'Park Lane 38'},
  { id: 12, name: 'William', address: 'Central st 954'},
  { id: 13, name: 'Chuck', address: 'Main Road 989'},
  { id: 14, name: 'Viola', address: 'Sideway 1633'}
]

let mysql = require('mysql');

let con = mysql.createConnection({
  host: "localhost",
  user: "yourusername",
  password: "yourpassword",
  database: "mydb"
});

con.connect(function(err) {
  if (err) throw err;
  con.query("SELECT name, address FROM customers", function (err, result, fields) {
    if (err) throw err;
    console.log(result);
  });
});

C:\Users\Your Name>node demo_db_select2.js

[
  { name: 'John', address: 'Highway 71'},
  { name: 'Peter', address: 'Lowstreet 4'},
  { name: 'Amy', address: 'Apple st 652'},
  { name: 'Hannah', address: 'Mountain 21'},
  { name: 'Michael', address: 'Valley 345'},
  { name: 'Sandy', address: 'Ocean blvd 2'},
  { name: 'Betty', address: 'Green Grass 1'},
  { name: 'Richard', address: 'Sky st 331'},
  { name: 'Susan', address: 'One way 98'},
  { name: 'Vicky', address: 'Yellow Garden 2'},
  { name: 'Ben', address: 'Park Lane 38'},
  { name: 'William', address: 'Central st 954'},
  { name: 'Chuck', address: 'Main Road 989'},
  { name: 'Viola', address: 'Sideway 1633'}
]

console.log(result[2].address);

Apple st 652

let mysql = require('mysql');

let con = mysql.createConnection({
  host: "localhost",
  user: "yourusername",
  password: "yourpassword",
  database: "mydb"
});

con.connect(function(err) {
  if (err) throw err;
  con.query("SELECT name, address FROM customers", function (err, result, fields) {
    if (err) throw err;
    console.log(fields);
  });
});

C:\Users\Your Name>node demo_db_select_fields.js

[
  {
    catalog: 'def',
    db: 'mydb',
    table: 'customers',
    orgTable: 'customers',
    name: 'name',
    orgName: 'name',
    charsetNr: 33,
    length: 765,
    type: 253,
    flags: 0,
    decimals: 0,
    default: undefined,
    zeroFill: false,
    protocol41: true
  },
  {
    catalog: 'def',
    db: 'mydb',
    table: 'customers',
    orgTable: 'customers',
    name: 'address',
    orgName: 'address',
    charsetNr: 33,
    length: 765,
    type: 253,
    flags: 0,
    decimals: 0,
    default: undefined,
    zeroFill: false,
    protocol41: true
  }
]

console.log(fields[1].name);

address

// Select with ordering and limiting
con.query("SELECT * FROM customers ORDER BY name ASC LIMIT 5", function (err, result) {
  if (err) throw err;
  console.log(result);
});

// Select distinct values
con.query("SELECT DISTINCT address FROM customers", function (err, result) {
  if (err) throw err;
  console.log(result);
});

// Select with calculations
con.query("SELECT COUNT(*) as total_customers FROM customers", function (err, result) {
  if (err) throw err;
  console.log("Total customers:", result[0].total_customers);
});

// Select with variables
const columnName = "name";
const tableName = "customers";
const sql = `SELECT ${columnName} FROM ${tableName}`;

con.query(sql, function (err, result) {
  if (err) throw err;
  console.log(result);
});

const mysql = require('mysql');

// Create connection
const con = mysql.createConnection({
  host: "localhost",
  user: "root",
  password: "password",
  database: "company_db"
});

// Connect to MySQL
con.connect((err) => {
  if (err) {
    console.error('Error connecting to MySQL:', err.message);
    return;
  }
  
  console.log('Connected to MySQL database');
  
  // Example 1: Select all records
  console.log('\n1. All customers:');
  con.query("SELECT * FROM customers", (err, result) => {
    if (err) {
      console.error('Error selecting all customers:', err.message);
      return;
    }
    console.log(result);
  });
  
  // Example 2: Select specific columns
  console.log('\n2. Customer names and addresses:');
  con.query("SELECT name, address FROM customers", (err, result) => {
    if (err) {
      console.error('Error selecting specific columns:', err.message);
      return;
    }
    console.log(result);
  });
  
  // Example 3: Select with ordering and limiting
  console.log('\n3. First 5 customers ordered by name:');
  con.query("SELECT * FROM customers ORDER BY name ASC LIMIT 5", (err, result) => {
    if (err) {
      console.error('Error selecting with order and limit:', err.message);
      return;
    }
    console.log(result);
  });
  
  // Example 4: Get field information
  console.log('\n4. Field information:');
  con.query("SELECT name, address FROM customers", (err, result, fields) => {
    if (err) {
      console.error('Error getting field information:', err.message);
      return;
    }
    console.log('Fields:', fields);
    
    // Close connection after all queries
    setTimeout(() => {
      con.end((err) => {
        if (err) {
          console.error('Error closing connection:', err.message);
          return;
        }
        console.log('\nConnection closed');
      });
    }, 1000);
  });
});