MySql GREATER ( > ) Operator Example

MySql GREATER ( > ) Operator Example


Posted in : Java Posted on : November 14, 2011 at 6:16 PM Comments : [ 0 ]

In this tutorial you will learn how to use '>' operator in sql queries in mysql using servlet.

MySql GREATER ( > ) Operator Example

In this tutorial you will learn how to use '>' operator in sql queries in mysql using servlet.

> (greater) operator in mysql compares the two operands to find the greater value from one of them and returns 1 if the statement is true otherwise returns 0 and null if both or either side of operand is declared to null. It returns all the greater value of a list form the specified number.

Example :

In this example first I created a table named userInfo for fetching the data. To use this mysql operator in servlet I created a class named MysqlGreater.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 the mysql query so we are required to connect with a database package (here I am using MySql)  that's why in further steps I perform the database connectivity with servlet using the java.sql package. In example to use the above operator I use the query "SELECT empId  >  deptId FROM userInfo". This query will return the value 1 if the value of empId field is greater than to the value of deptId, else return 0 and null if both or either side of these operands value is getting null.

This operator can also be used as "SELECT name, empId FROM userInfo WHERE empId > 5". This query will return list of names and empId from the table userInfo of which empId is greater than the 5.

MysqlGreater.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 MysqlGreater 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/data";
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 empId > deptId FROM userInfo";

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

out.println("<html>");
out.println("<table>");
out.println("<th>empId > deptId</th>");
while(rs.next())
{
String em= rs.getString("empId > deptId");

out.println("<tr>");
out.println("<td align= middle>"+em+"</td>");
out.println("</tr>");
}
out.println("</table>");
out.println("</html>");
}
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>MysqlGreater</servlet-name>
<servlet-class>MysqlGreater</servlet-class>
</servlet>

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

</web-app>

Output :

Database table  userInfo has the following data following :

When you will execute the servlet example using the query 'select empId > deptId from userInfo' you will get the output like as :

But when you will execute the servlet example using the query 'select name,empId from userInfo where empId > 5 ' you will get the value as :

Download Source Code

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