Basically Date is used to extract the data from a table in database . Suppose you want to find and extract the data from database for particular date then you can do this with the Date statement .
Example ->
Table name -> student

 Student_name            Student_Age          Student_Id        Date
   Mukesh                  23                     1          2013-12-12          
   Ayush                   24                     2          2013-12-13
   Ishan                   20                     4          2012-12-12

Suppose you want to extract the information of date 2013-12-12 and more than this .

select * from student where Date >= 2013-12-12 ;

Output :

  Student_name            Student_Age          Student_Id        Date
     Mukesh                  23                     1          2013-12-12          
     Ayush                   24                     2          2013-12-13
     Ishan                   20                     4          2012-12-12

Now suppose you want to retrieve the data of date after than 2013-12-12 and before 2013-12-13 .

select * from student where Date < ' 2013-12-13 ' and Date >= ' 2013-12-12 ' ; 

Output :

Student_name            Student_Age          Student_Id        Date
   Mukesh                  23                      1          2013-12-12          
   Ishan                   20                      4          2012-12-12

If you want to compare the dates then you have to use Between operator between them like this..see below :
Syntax :

   select * from student where Date Between ?2012-12-12  and ?2013-12-12 ;

Suppose you want to retrieve only one date from database then you can also do :

select * from student where cast ( datedifference (day , 0 , yourdate ) as datetime ) = ?2012-12-12?