Returns NULL if any argument is NULL.
The minimum base is 2.
The maximum base is 36.
If to_base is a negative number, N is regarded as a signed number.
Otherwise, N is treated as unsigned.
CONV() works with 64-bit precision.
mysql>
mysql> SELECT CONV('a',16,2);
+----------------+
| CONV('a',16,2) |
+----------------+
| 1010 |
+----------------+
1 row in set (0.00 sec)
mysql>