DROP PROCEDURE scope_test;
/

CREATE PROCEDURE scope_test( ) 
BEGIN
    DECLARE outer_variable VARCHAR(30); 
    SET outer_variable = 'Sam';

    BEGIN				                            -- start inner block
        DECLARE inner_variable VARCHAR(30); 
        SET  inner_variable = 'This is my inner variable'; 
        SET  outer_variable = 'This is the outer variable'; 
--	    SELECT inner_variable, outer_variable;      -- both are OK
    END; 

--  SELECT outer_variable; 					-- this is OK
    SELECT inner_variable; 					-- this is ERROR
END;
/

CALL scope_test();