Node.js MySQL Where

🚀 Node.js MySQL – WHERE Clause

The WHERE clause is used to filter records based on specific conditions.

We’ll use mysql2 (recommended) for all examples.

✅ 1. Install mysql2

✅ 2. Connect to MySQL Database

✅ 3. Basic WHERE Clause

Fetch a user with a specific id:

Output example:

✅ 4. Multiple Conditions (AND / OR)

AND Condition

OR Condition

✅ 5. Comparison Operators

// Greater than
connection.query("SELECT * FROM users WHERE id > ?", [2], (err, rows) => console.log(rows));

// Less than
connection.query("SELECT * FROM users WHERE id < ?", [5], (err, rows) => console.log(rows));

// Not equal
connection.query("SELECT * FROM users WHERE id != ?", [3], (err, rows) => console.log(rows));

// Greater than

connection.query("SELECT * FROM users WHERE id > ?", [2], (err, rows) => console.log(rows));

// Less than

connection.query("SELECT * FROM users WHERE id < ?", [5], (err, rows) => console.log(rows));

// Not equal

connection.query("SELECT * FROM users WHERE id != ?", [3], (err, rows) => console.log(rows));

✅ 6. LIKE Operator (Search by Pattern)

// Find users whose name starts with 'J'
connection.query("SELECT * FROM users WHERE name LIKE ?", ["J%"], (err, rows) => console.log(rows));

// Find users whose email contains 'example'
connection.query("SELECT * FROM users WHERE email LIKE ?", ["%example%"], (err, rows) => console.log(rows));

// Find users whose name starts with 'J'

connection.query("SELECT * FROM users WHERE name LIKE ?", ["J%"], (err, rows) => console.log(rows));

// Find users whose email contains 'example'

connection.query("SELECT * FROM users WHERE email LIKE ?", ["%example%"], (err, rows) => console.log(rows));

✅ 7. IN Operator (Multiple Values)

✅ 8. Using Async/Await with WHERE Clause

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

async function getUserById(id) {
const connection = await mysql.createConnection({
host: "localhost",
user: "root",
password: "",
database: "mydb"
});

const [rows] = await connection.execute("SELECT * FROM users WHERE id = ?", [id]);
console.log(rows);

await connection.end();
}

getUserById(1);

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

async function getUserById(id) {

const connection = await mysql.createConnection({

host: "localhost",

user: "root",

password: "",

database: "mydb"

});

const [rows] = await connection.execute("SELECT * FROM users WHERE id = ?", [id]);

console.log(rows);

await connection.end();

}

getUserById(1);

✅ 9. Tips & Best Practices

Always use prepared statements (?) to prevent SQL injection.
Combine WHERE with ORDER BY, LIMIT for efficient queries.
Use async/await for better readability in production code.
Use IN and LIKE for flexible search queries.

Node.js MySQL Where