Node.js MySQL SELECT Unique Record

Node.js MySQL SELECT Unique Record

In this tutorial, you will learn how to retrieve specific or unique records from a MySQL table using Node.js. We will use the WHERE clause to find a record based on a specific condition and the LIKE operator with wildcards to search for records that match a particular pattern.

More:- UPDATEGADH

1. Retrieving a Unique Record Using WHERE Clause

First, create a JavaScript file named selectwhere.js inside a folder called DBexample. This script connects Node.js to a MySQL database and retrieves a specific record from the employees table using an employee ID.

Example

var mysql = require('mysql');

var con = mysql.createConnection({
  host: "localhost",
  user: "root",
  password: "12345",
  database: "updategadh"
});

con.connect(function(err) {
  if (err) throw err;

  con.query("SELECT * FROM employees WHERE id = '1'", function (err, result) {
    if (err) throw err;

    console.log(result);
  });
});

Explanation

• First, we import the MySQL module using require('mysql').
• Next, mysql.createConnection() is used to connect Node.js with the updategadh database.
• The SELECT query uses the WHERE clause to find the employee whose id is equal to 1.
• The retrieved record is displayed in the terminal using console.log(result).

To execute the file, open the terminal, navigate to the DBexample folder, and run:

node selectwhere.js

The command will display the employee record with id = 1 in the console.

2. Retrieving Records Using Wildcard with LIKE Operator

You can also use the SQL LIKE operator to retrieve records that match a specific pattern. Create another file named selectwildcard.js inside the same DBexample folder.

YT:- DecodeIT

Example

var mysql = require('mysql');

var con = mysql.createConnection({
  host: "localhost",
  user: "root",
  password: "12345",
  database: "updategadh"
});

con.connect(function(err) {
  if (err) throw err;

  con.query("SELECT * FROM employees WHERE city LIKE 'A%'", function (err, result) {
    if (err) throw err;

    console.log(result);
  });
});

Explanation

• The LIKE operator is used for pattern matching in SQL queries.
• The query SELECT * FROM employees WHERE city LIKE 'A%' retrieves employee records where the city name starts with the letter A.
• The % wildcard represents any number of characters after the letter A.

Run the script using the following command:

node selectwildcard.js

This will retrieve and display all employee records where the city name begins with A.

Summary

In this tutorial, you learned how to use Node.js with MySQL to retrieve records from a database. You learned how to use the WHERE clause to retrieve a specific record and the LIKE operator with wildcards to perform pattern-based searches.

These techniques are useful for creating database-driven applications that need to search and retrieve information efficiently.

Keywords

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