`log` function doesn't handle strings the same as MySql

[angelamayxie]

dolt

tmp/main*> select log("10","100");
+-----------------+
| log("10","100") |
+-----------------+
| 2               |
+-----------------+
1 row in set (0.00 sec) 


tmp/main*> select log("10","100f");
invalid type: string
tmp/main*> select log("10asdf","100f");
invalid type: string
tmp/main*> select log("a10asdf","b100f");
invalid type: string

mysql

mysql> select log("10","100");
+-----------------+
| log("10","100") |
+-----------------+
|               2 |
+-----------------+
1 row in set (0.00 sec)

mysql> select log("10","100f");
+------------------+
| log("10","100f") |
+------------------+
|                2 |
+------------------+
1 row in set, 1 warning (0.00 sec)

mysql> select log("10asdf","100f");
+----------------------+
| log("10asdf","100f") |
+----------------------+
|                    2 |
+----------------------+
1 row in set, 2 warnings (0.00 sec)

mysql> select log("a10asdf","b100f");
+------------------------+
| log("a10asdf","b100f") |
+------------------------+
|                   NULL |
+------------------------+
1 row in set, 2 warnings (0.00 sec)

some of this is related to #9733

[angelamayxie]

note that mysql has warnings for string truncation