SQL函数 Convert,dateadd

1.SQL中CONVERT转化函数的用法

格式:
CONVERT(data_type,expression[,style])

说明:
此样式一般在时间类型(datetime,smalldatetime)与字符串类型(nchar,nvarchar,char,varchar)
相互转换的时候才用到.

例子:
SELECT CONVERT(varchar(30),getdate(),101) now
结果为:
now
---------------------------------------
|09/15/2001

===================================================================

style数字在转换时间时的含义如下:

------------------------------------------------------------------------------------------------------------
Style(2位表示年份)   |  Style(4位表示年份)   |   输入输出格式                                    
------------------------------------------------------------------------------------------------------------
0                               | 100                           |   mon dd yyyy hh:miAM(或PM)              
------------------------------------------------------------------------------------------------------------
1                               |  101   美国                |   mm/dd/yy                                       
------------------------------------------------------------------------------------------------------------
2                               |  102    ANSI               |   yy-mm-dd                                        
------------------------------------------------------------------------------------------------------------
3                               |  103    英法                |   dd/mm/yy                                       
------------------------------------------------------------------------------------------------------------
4                               |  104    德国                |   dd.mm.yy                                        
------------------------------------------------------------------------------------------------------------
5                               |  105    意大利             |   dd-mm-yy                                        
------------------------------------------------------------------------------------------------------------
6                               |  106                            |   dd mon yy                                        
------------------------------------------------------------------------------------------------------------
7                               |  107                            |   mon dd,yy                                        
------------------------------------------------------------------------------------------------------------
8                               |  108                            |   hh:mm:ss                                         
------------------------------------------------------------------------------------------------------------
9                               |  109                            |   mon dd yyyy hh:mi:ss:mmmmAM(或PM)
------------------------------------------------------------------------------------------------------------
10                             |  110    美国                 |   mm-dd-yy                                         
------------------------------------------------------------------------------------------------------------
11                             |  111    日本                 |   yy/mm/dd                                        
------------------------------------------------------------------------------------------------------------
12                             |  112    ISO                  |   yymmdd                                           
------------------------------------------------------------------------------------------------------------
13                             |  113     欧洲默认值     |   dd mon yyyy hh:mi:ss:mmm(24小时制)  
------------------------------------------------------------------------------------------------------------
14                             |  114                            |   hh:mi:ss:mmm(24小时制)                    
------------------------------------------------------------------------------------------------------------
20                             |  120     ODBC 规范     |    yyyy-mm-dd hh:mi:ss(24小时制)         
------------------------------------------------------------------------------------------------------------
21                             |   121                           |    yyyy-mm-dd hh:mi:ss:mmm(24小时制) 
-
-----------------------------------------------------------------------------------------------------------

 

 

 2.SQL Server Date 函数之DATEADD()

DATEADD() 函数在日期中添加或减去指定的时间间隔。

语法

DATEADD(datepart,number,date)

date 参数是合法的日期表达式。number 是您希望添加的间隔数;对于未来的时间,此数是正数,对于过去的时间,此数是负数。

datepart 参数可以是下列的值:

datepart

缩写

yy, yyyy

季度

qq, q

mm, m

年中的日

dy, y

dd, d

wk, ww

星期

dw, w

小时

hh

分钟

mi, n

ss, s

毫秒

ms

微妙

mcs
纳秒 ns

posted on 2016-04-28 14:41  可爱的春哥  阅读(875)  评论(0编辑  收藏  举报

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