How to create function in MySQL

drop function if exists function_name ;delimiter $$CREATE FUNCTION function_name [ (parameter datatype [, parameter datatype]) ]RETURNS return_datatypeBEGIN    -- statementsEND$$-- for use the function select function_name(parameter);

drop function if exists countscoll;delimiter $$CREATE FUNCTION countscoll( cit int ) returns int begin    declare tota int ;   set tota = ( select count(*) from school    where city = cit );   return tota ;end$$delimiter ;select countscoll("new york");