and or  commands and  order by .

hav a big database 

eg: id , name , l name,  ..

order by alphabetical .."DESC" is reverse ..

http://www.w3schools.com/sql/sql_orderby.asp

and or command for  get specify data's from a big table.

http://www.w3schools.com/Sql/sql_and_or.asp

thsts is today. stupid sally