mysql数字转换
mysql如何将 decimal数据 15.1000 15.0000 15.2100 
等数据转换为 15.1 15 15.21

------解决方案--------------------
mysql> select cast(1.0000 as decimal);
+-------------------------+
| cast(1.0000 as decimal) |
+-------------------------+
| 1 | 
+-------------------------+
1 row in set (0.00 sec)
------解决方案--------------------
mysql> select cast(1.03050 as decimal);
+--------------------------+
| cast(1.03050 as decimal) |
+--------------------------+
| 1 |
+--------------------------+
1 row in set (0.00 sec)
------解决方案--------------------
select cast(aa as decimal);
------解决方案--------------------
select cast(15.1000 as char)+0
先转为字符串再转为数字，会自动去掉小数点后的0，其它round，truncate函数都必须指定确切的小数位，不能自动判断