Java Program to Join Contents of More than One Table & Display in JDBC

// Java Program to Join Contents
// of More than One Table & Display in JDBC

// Step 1: Importing DB files

// Provides the API for accessing and processing
// data stored in a data source
import java.sql.*;

// Class for Joining of multiple tables
public class GFG {

    // Main driver method
    public static void main(String[] args)
    {

        // Display message
        System.out.println(
            "Joining 2 MySQL tables using Natural Join");

        // DB 'Connection' object of Connection class
        Connection con = null;

        // Try block to check exceptions
        try {
            // Step 2: Load and register drivers

            // Loading driver
            // Jars(relevant) or mysql-connector-java-8.0.22
            // in build path of project
            Class.forName("com.mysql.cj.jdbc.Driver");

            // Registering driver

            // test is database name here
            // serverTimezone=UTC, if not provided we will
            // have java.sql.SQLException
            // Credentials here are root/""
            // i.e. username is root
            // password is ""

            // Step 3: Establishing a connection
            con = DriverManager.getConnection(
                "jdbc:mysql://localhost:3306/test?serverTimezone=UTC",
                "root", "");

            // Try block to check java exceptions
            try {

                // Step 4: Write a statement
                // Join
                Statement st = con.createStatement();
                // Combining two tables in query using
                // NATURAL JOIN studentsdetails columns :
                // Name,caste,NeetMarks,gender
                // studentspersonaldetails columns :
                // Name,Address,email

                // In both tables, connecting columns are
                // Name is taken Here res will have the
                // data from
                // both studentsdetails and
                // studentspersonaldetails whenever "Name"
                // in both tables are matched join
                ResultSet res = st.executeQuery(
                    "SELECT *FROM "
                    + "studentsdetails"
                    + " NATURAL JOIN "
                    + "studentspersonaldetails");

                // Step 5: Execute the query
                System.out.println("   StuName"
                                   + "    Gender"
                                   + "     Caste  "
                                   + "Neet Marks"
                                   + "     Email");

                // Step 6: Process the statements
                // Iterate the resultset and retrieve the
                // required fields
                while (res.next()) {
                    String name = res.getString("Name");
                    String gender = res.getString("gender");
                    String caste = res.getString("caste");
                    String neetMarks
                        = res.getString("NeetMarks");
                    String email = res.getString("email");

                    // Beautification of output
                    System.out.format(
                        "%10s%10s%10s%10s%20s\n", name,
                        gender, caste, neetMarks, email);
                }

                // Step 7: Close the connection
                con.close();
            }

            // Catch block to handle DB exceptions
            catch (SQLException s) {

                // If there is error in SQL query, this
                // exception occurs
                System.out.println(
                    "SQL statement is not executed!");
            }

            // Catch block to handle generic java
            // exceptions
        }
        catch (Exception e) {

            // General exception apart from SQLException are
            // caught here
            e.printStackTrace();
        }
    }
}