## Query union ?

Hi everyone and good day.

I have two queries for this output:
Code:
```+--------------+-------------+------------+--------+-------------+-------------------+
| application  | StartDate   | EndDate    | Number | Number days | Number for day    |
+--------------+-------------+------------+--------+-------------+-------------------+
| NULL         | 01/01/2011  | 26/06/2011 |  58348 |   176       | 332               |
| Report       | 01/01/2011  | 26/06/2011 |   6987 |   176       | 40                |
+--------------+-------------+------------+--------+-------------+-------------------+

+--------------+-------------+------------+--------+-------------+-------------------+
| application  | StartDate   | EndDate    | Number | Number days | Number for day    |
+--------------+-------------+------------+--------+-------------+-------------------+
| NULL         | 01/01/2012  | 26/06/2012 |  56937 |   177       | 322               |
| Report       | 01/01/2012  | 26/06/2012 |   6314 |   177       | 36                |
+--------------+-------------+------------+--------+-------------+-------------------+```
I need:
1. Replace in the output NULL with `Total` alias;
2. Automatically calculate this formula:
Code:
`( Number(value of 2th query) - Number(value of 1th query) ) / Number(value of 2th query)`
e.g.: ( 56937 - 58348 ) / 58348 ====> -0.0241

How to with only query?
Code:
```mysql> SELECT
*
FROM
(
SELECT
application,
DATE_FORMAT(
MAKEDATE(YEAR(CURDATE()) - 1, 1),
'%d/%m/%Y'
) `StartDate`,
DATE_FORMAT(
'%d/%m/%Y'
) `EndDate`,
COUNT(*) `Number`,
DATEDIFF(
MAKEDATE(YEAR(CURDATE()) - 1, 1)
) `Number days`,
FORMAT(
(
COUNT(*) / DATEDIFF(
MAKEDATE(YEAR(CURDATE()) - 1, 1)
)
),
0
) `Number for day`
FROM
tbl_backup
WHERE
1
AND `myDate` BETWEEN MAKEDATE(YEAR(CURDATE()) - 1, 1)
AND DATE_ADD(CURDATE(), INTERVAL - 1 YEAR)
GROUP BY
application WITH ROLLUP
) t
ORDER BY
t.`Number` DESC
LIMIT 1;

SELECT
*
FROM
(
SELECT
application,
DATE_FORMAT(
MAKEDATE(YEAR(CURDATE()), 1),
'%d/%m/%Y'
) `StartDate`,
DATE_FORMAT(CURDATE(), '%d/%m/%Y') `EndDate`,
COUNT(*) `Number`,
DATEDIFF(
CURDATE(),
MAKEDATE(YEAR(CURDATE()), 1)
) `Number days`,
FORMAT(
(
COUNT(*) / DATEDIFF(
CURDATE(),
MAKEDATE(YEAR(CURDATE()), 1)
)
),
0
) `Number for day`
FROM
tbl_backup
WHERE
1