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Querying Data from Table using Node
In this article, we will see how to select or query the data from a database based on different table fields and columns.
Before proceeding, please check the following steps are already executed −
mkdir mysql-test
cd mysql-test
npm init -y
npm install mysql
The above steps are for installing the Node - mysql dependecy in the project folder.
Select Data from Table Using Node
Create a new file with the following name – app.js
Copy and Paste the following code snippet in this file.
Now, run the following command to check the output of the above program.
>> node app.js
Example
// Checking the MySQL dependency – if exists
var mysql = require('mysql');
// Creating connection with the mysql database
var con = mysql.createConnection({
host: "localhost",
user: "yourusername",
password: "yourpassword",
database: "mydb"
});
con.connect(function(err) {
if (err)
console.log("Unable to connect to DB ", err);
con.query("SELECT * FROM students", function (err, result, fields) {
if (err) throw err;
console.log(result);
});
});Output
It will return all the records present in the students table:
[ RowDataPacket { id: 1, name: 'John', address: 'Delhi'},
RowDataPacket { id: 2, name: 'Pete', address: 'Mumbai'},
RowDataPacket { id: 3, name: 'Amy', address: 'Hyderabad'},
RowDataPacket { id: 4, name: 'Hannah', address: 'Mumbai'},
RowDataPacket { id: 5, name: 'Mike', address: 'Delhi'}]Querying Data from Table Using Node
The following code snippet gives us an example how we can use SQL queries to query and select data from Node.
Example
// Checking the MySQL dependency – if exists
var mysql = require('mysql');
// Creating connection with the mysql database
var con = mysql.createConnection({
host: "localhost",
user: "yourusername",
password: "yourpassword",
database: "mydb"
});
con.connect(function(err) {
if (err)
console.log("Unable to connect to DB ", err);
con.query("SELECT * FROM student where address='Delhi'; ", function (err, result, fields) {
if (err) throw err;
console.log(result);
});
});Output
It will return result based on our filter −
[ RowDataPacket { id: 1, name: 'John', address: 'Delhi'},
RowDataPacket { id: 5, name: 'Mike', address: 'Delhi'}]
Updated on: 28-Apr-2021
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