/*******************************************************************
/* global variables
/* this example only works in SQL*PLUS (or SQL Developer)
/******************************************************************/
VARIABLE how_many  NUMBER
/

DECLARE 
    cnt number;
BEGIN
    select count(*) into cnt from student;
    :how_many := cnt;				-- bind variable :how_many to cnt				
END;
/

select :y from dual
/

print y						-- you can even use PRINT