mysql很不专业

wangwengwu

mysql> SELECT 3/5;
-> 0.60
整数相除就默认变float了?一般c程序员都知道,整数相除默认整数
看看postgres和python的专业性:
postgres=# select 3/5;
?column?
----------
0
(1 row)
Python 2.6.5 (r265:79063, Apr 16 2010, 13:57:41)
[GCC 4.4.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> 3/5;
0
>>>

按照程序员习惯,想要获得浮点数,必须:
postgres=# select 3/5.0;
?column?        
------------------------
0.60000000000000000000
(1 row)
Python 2.6.5 (r265:79063, Apr 16 2010, 13:57:41)
[GCC 4.4.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> 3/5.0;
0.59999999999999998

更不专业的是,居然被零除,结果是null:
mysql> SELECT 102/(1-1);
-> NULL

专业的应该是:
postgres=# select 102/(1-1);
ERROR:  division by zero

>>> 102/(1-1);
Traceback (most recent call last):
File "", line 1, in
ZeroDivisionError: integer division or modulo by zero