You can use your database as a simple calculator

Saw this in the MySQL docs. I'm assuming this only works for relational databases.

I don't know if it's very useful but definitely interesting.

MariaDB[] > SELECT SIN(PI()/4), (4+1)*5;
+------------------+---------+
| SIN(PI()/4)      | (4+1)*5 |
+------------------+---------+
| 0.70710678118655 |      25 |
+------------------+---------+
1 row in set (0.02 sec)

postgres=# SELECT SIN(PI()/4), (4+1)*5;
        sin         | ?column?
--------------------+----------
 0.7071067811865475 |       25
(1 row)