Total purchase = host variable

VARIABLE  g_purchase_num NUMBER(3)

BEGIN
g_purchase_num := 500;
END

DECLARE
lv_rating CHAR (4);
BEGIN
IF :g_purchase_num > 200 THEN
lv_rating  := ‘HIGH’;
ELSEIF :g_purchase_num < 200 AND  :g_purchase_num > 100 THEN
lv_rating  := ‘MID’;
ELSE
lv_rating  := ‘LOW’;
END IF;
DBMS_OUTPUT.PUT_LINE(lv_rating);
END;