Executing SELECT query using Java
Java MySQL Database

Executing SELECT query using Java

Editorial Team
Editorial Team

Follow us on Discord or Telegram to get access to free tutorials and updates.

n my previous articles about Java JDBC, I showed How to connect Java applications to MySQL. In this article, I will show you how to execute a SELECT query from your Java application.

Requirements

  • A MySQL table with one or more records – If you don’t know how to create a table and insert records into it, read this article first.

Here’s how my table looks like.

1JohnAustralia
2LeeChina

Importing packages

Before starting, import the following package.

import java.sql.*;

Creating database connection

To execute our SQL query from Java, we must create a connection first. The getConnection() method takes connection url as the first parameter and username and password as the second and third parameters.

String connUrl="jdbc:mysql://localhost/javadb?;
Connection conn=DriverManager.getConnection(connUrl,"database_username","password");
/*Replace database_name with your database name and password with your database password.*/

Creating a SELECT query

First, let’s create a simple SELECT query.

SELECT * FROM USERS;

This will return all records from the table. Now let’s put this to our Java code.

Statement st=conn.createStatement();
ResultSet rs=st.executeQuery("SELECT * FROM users");
//Replace users with your database name

Displaying the result

Here, we are going to display the name and age from the result.

while(rs.next()) 
{ 
    name=rs.getString("_name");
    age=rs.getString("country")
    System.out.println("Name :" + name + "and Country :" + country);
}
conn.close(); //closing the connection

Full source code of the program is:

import java.sql.*;
public class JavaDemoApp {
    public static void main(String[] args) 
    {
        try
        {
            String name="";
            Class.forName("com.mysql.cj.jdbc.Driver");
            String connUrl="jdbc:mysql://localhost/javadb?";
    Connection conn=DriverManager.getConnection(connUrl,"root","");
    String sql="select * from users";
    Statement st=conn.createStatement();
    ResultSet rs = st.executeQuery(sql);
            while(rs.next()) 
            { 
                name=rs.getString("_name");
                JOptionPane.showMessageDialog(rootPane, name);
            }
            conn.close();
        }
        catch(Exception ex)
        {
            System.out.println(ex.getMessage());
        }
    }
}