最近因为工作的需求，需要对MysqL中数字进行格式化，但发现网上的资料较少，索性自己总结一下，方便自己也帮助有需要的朋友们，下面话不多说，来一起看看详细的介绍：

一、format函数：

格式化浮点数 format(number,length);

介绍：Formats the number X to a format like '#,###,###.##',rounded to D decimal places,and returns the result as a string. If D is 0,the result has no decimal point or fractional part. D should be a constant value.

示例代码

MysqL> SELECT FORMAT(12332.123456,4);
 -> '12,332.1235' 
MysqL> SELECT FORMAT(12332.1,332.1000' 
MysqL> SELECT FORMAT(12332.2,0);
 -> '12,332'

二、rpad 和 lpad 给定位数，不足补充自定义字符

RPAD:

Returns the string str,right-padded with the string padstr to a length of len characters. If str is longer than len,the return value is shortened to len characters.      

示例代码  

MysqL> SELECT RPAD('hi',5,'?'); 
  -> 'hi???'
 MysqL> SELECT RPAD('hi',1,'?'); 
  -> 'h'
MysqL>SELET RPAD(12,0);
  ->12000

This function is multi-byte safe.

LPAD:

Returns the string str,left-padded with the string padstr to a length of lencharacters. If str is longer than len,the return value is shortened to lencharacters.

示例代码

MysqL> SELECT LPAD('hi',4,'??');
 -> '??hi' 
MysqL> SELECT LPAD('hi','??');
 -> 'h' 

MysqL>SELECT LPAD(12,0)
  ->'00012'