MySQL Bugs: #5929: Traditional: MOD with 0 divisor should return error

Bug #5929	Traditional: MOD with 0 divisor should return error
Submitted:	6 Oct 2004 17:24	Modified:	4 Jan 2007 0:16
Reporter:	Trudy Pelzer	Email Updates:
Status:	Verified
Category:	Server: Errors	Severity:	S3 (Non-critical)
Version:	5.0.2-alpha-debug	OS:	Linux (SuSE 9.1)
Assigned to:		Target Version:
Triage:	Triaged: D2 (Serious) / R4 (High) / E4 (High)

Description:
When sql_mode='traditional', any use of the MOD function 
where the divisor is zero (0) must return SQLSTATE 22012  
division by zero. Currently, the function is returning NULL 
on a SELECT MOD(x,0). INSERTs and UPDATEs that use 
MOD are working correctly. 

How to repeat:
mysql> set sql_mode='traditional'; 
Query OK, 0 rows affected (0.00 sec) 
 
mysql> create table t1 (col1 tinyint) engine=innodb; 
Query OK, 0 rows affected (0.01 sec) 
 
mysql> insert into t1 values(50); 
Query OK, 1 row affected (0.00 sec) 
 
mysql> select mod(col1,0) from t1; 
+-------------+ 
| mod(col1,0) | 
+-------------+ 
|        NULL | 
+-------------+ 
1 row in set (0.00 sec) 
-- This is the incorrect response. The result should be 
SQLSTATE 22012 division by zero and no result set. 
 
mysql> insert into t1 values(mod(50,0)); 
ERROR 1365 (22012): Division by 0 
-- This is the correct response. 
 
mysql> select * from t1; 
+------+ 
| col1 | 
+------+ 
|   50 | 
+------+ 
1 row in set (0.00 sec) 
 
mysql> update t1 set col1=mod(col1,0); 
ERROR 1365 (22012): Division by 0 
-- This is the correct response. 
 
mysql> select * from t1; 
+------+ 
| col1 | 
+------+ 
|   50 | 
+------+ 
1 row in set (0.00 sec) 
-- This is the expected result.

Verified against latest BK source tree.

Yet another one. The warning is also generated only in traditional mode due to
MODE_ERROR_ON)DIVISION_BY_ZERO is unset by default.

mysql> select * from t1 where mod(col1,0) = 1;
Empty set, 1 warning (47.40 sec)

mysql> show warnings;
+-------+------+---------------+
| Level | Code | Message       |
+-------+------+---------------+
| Error | 1365 | Division by 0 |
+-------+------+---------------+
1 row in set (3.04 sec)

These issues are due to Items' got evaluated with no abort_on_warning flag set, so all
the faulty arithmetics in SELECT path just goes through.

Hello Timothy,
this bug is too big for the maintenance team. It's not a bug, but a documented
limitation. I am claiming it anyway.