mysql query to check the date

[preethi Ayyappan]

Hi,
I am doing a program like phone booking.Now what i need is, a person who had booked a product already in last 15 days should not book another time within that 15 days.what is the mysql query to check whether he had booked already within last 15 days.

Thanks.

[Dag Corell]

http://dev.mysql.com/doc/refman/5.0/en/date-and-time-functions.html#function_datediff

[preethi Ayyappan]

Hi,
Thank you for your reply.
i want to check whether the systemdate and registered date is greater than 20.if yes i want to update the flag and registered date.if not ,it should go to else part.But my code does not goes to the else part even the condition is false.where am i wrong?my code follows:

  
try
{
Class.forName
("com.mysql.jdbc.Driver").newInstance();
conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test", "dialer", "1234");
st = conn.createStatement();
rs=st.executeQuery("select * from exist where datediff(sysdate(),regdate)>20 and consumernum='"+ cnum +"'");
if(rs.next())
{
st.executeUpdate("UPDATE exist SET flag='1',regdate=sysdate() WHERE consumernum='"+ cnum +"'"); 
System.out.println("your number is registered");
  }
else
{
System.out.println("you  r not eligible to register");
} 
 }
  

please help me to find my error.

Thanks.

[preethi Ayyappan]

I got the result. Thanks