Query need to subtract the date in seconds.

[Joaquin Henriquez Alzola]

Hi Guys

I am taking two values from two different tables:
mysql> select sum(t.value) from (select value from radcheck where username='test1' and attribute='dayA_to_dayB' union all select value from raduser_connection_time where username='test1') t;
+--------------+
| sum(t.value) |
+--------------+
| 17888 |
+--------------+
1 row in set (0.00 sec)

mysql>

And I need to subtract in the same query the TIME_TO_SEC(NOW()) from those 17888 (t.value).

Any guidance?

Thanks

PD: I am newbi to this.