Using this function we can retrieve random row from a table in database . Mostly it is used in online exam , for random passwords etc .
Every Database has their own syntax for random function .
Syntax for MySQL Database

select col_name from table_name order by rand ( ) limit 1 ;

Syntax for SQL Database

select top 1 col_name from table order by new id ( ) ;

Syntax for Oracle Database

select col_name from ( select col_name from table name  order by dbmsName_random.value ) where rownum =1

Syntax for PostgreSQL Database

select col_name from table_name order by rand ( ) limit 1 ;

Example ->
Table name -> student

 **Student_name**     **Student_Age**    **Student_Id**
     Mukesh                    23            1
     Ayush                     24            2
     Ishan                     20            4
     Pranav                    35            7   
     Abhishek                  26            8
     Ravi                      25            3

If you want student name should be display in random order then you can do with rand ( ) function . See below

Select * from student order by rand ( ) ;

Output ->

**Student_name**     **Student_Age**    **Student_Id**
  Abhishek                  26                  8
  Ayush                     24                  2
  Mukesh                    23                  1
  Ravi                      25                  3
  Ishan                     20                  4
  Pranav                    35                  7