Node.js MySQL Where

In Node.js MySQL, the WHERE clause is used in a SQL statement to filter and retrieve specific rows from a table that meet a specific condition. In this tutorial, we'll discuss how to use the WHERE clause in Node.js MySQL.

Syntax

The basic syntax for using the WHERE clause in a MySQL query is as follows:

SELECT column1, column2, ...
FROM table_name
WHERE condition;

The WHERE clause specifies the condition that must be met for a row to be selected.

Example

Assuming we have a users table with columns id and name, the following Node.js MySQL query selects all users with id greater than 2:

const mysql = require('mysql');

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

connection.connect();

const sql = 'SELECT * FROM users WHERE id > 2';

connection.query(sql, (error, results, fields) => {
  if (error) throw error;
  console.log(results);
});

connection.end();

Output

The output of the above example should be a list of all users with id greater than 2.

Explanation

In the example above, we used Node.js MySQL to connect to a MySQL database and select all users with an id greater than 2. We created a MySQL connection using the mysql module, specified the SQL query using the WHERE clause with the > operator, and executed the query using the connection.query() method. Finally, we logged the result to the console.

Use

The WHERE clause is used to filter rows that meet a specific condition in a MySQL database query. This allows you to retrieve specific rows that match a certain criteria, which can be useful for displaying or manipulating data.

Important Points

• The SQL statement that includes a WHERE clause should be properly sanitized to prevent SQL injection attacks.
• The WHERE clause condition can include multiple conditions that are separated by logical operators such as AND, OR, and NOT.
• The MySQL WHERE clause supports a wide range of operators including comparison, logical, and custom operators.

Summary

In this tutorial, we discussed how to use the WHERE clause in Node.js MySQL to filter rows that meet specific criteria. We covered the syntax, example, output, explanation, use, and important points of using the WHERE clause in Node.js MySQL. With this knowledge, you can now use Node.js MySQL to select data from a MySQL database based on specific criteria.