MySql GREATEST ( ) Function Example

In this tutorial you will learn how to use mysql's "greatest()" function in servlet.

MySql GREATEST ( ) Function Example

In this tutorial you will learn how to use mysql's "greatest()" function in servlet.

GREATEST() function in mysql gives the greatest number from the list passed as an argument of this function.

Example :

In this example first I created a servlet class named MysqlGreatest.java which extends the class HttpServlet to support the http functionality to servlet, into which I defined the doGet() method into which the object's of HttpServeltRequest and HttpServletResponse are created. Since we have to use mysql's greatest() function in servlet so we are required to connect with the database package (here I am using MySql)  that's why in this example I perform the database connectivity with servlet using the java.sql package in java. To use this function I used the query "SELECT GREATEST(36, 45, 54,63, 27,72,18)". This query will return the greatest value 72.

MysqlGreatest.java

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.SQLException;
import java.sql.DriverManager;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class MysqlGreatest extends HttpServlet
{
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException
{
response.setContentType("text/html");
PrintWriter out= response.getWriter();

String className= "com.mysql.jdbc.Driver";
String url= "jdbc:mysql://192.168.10.13";
String user= "root";
String password= "root";

Connection con;
PreparedStatement ps;
ResultSet rs;

try
{
Class.forName(className);
con= DriverManager.getConnection(url, user, password);

String sql= "SELECT GREATEST(36, 45, 54,63, 27,72,18)";

ps= con.prepareStatement(sql);
rs= ps.executeQuery();

while(rs.next())
{
out.println("Greatest Number is : "+rs.getString(1));
}
}
catch(SQLException sx)
{
out.println(sx);
}
catch(ClassNotFoundException cx)
{
out.println(cx);
}
}
}

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<display-name>mysqlComparisonFunctionAndOperator</display-name>
<servlet>
<servlet-name>MysqlGreatest</servlet-name>
<servlet-class>MysqlGreatest</servlet-class>
</servlet>

<servlet-mapping>
<servlet-name>MysqlGreatest</servlet-name>
<url-pattern>/MysqlGreatest</url-pattern>
</servlet-mapping>

</web-app>

Output :

When you will execute the servlet example you will get the output like as :

Download Source Code