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  • 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
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  • 原文地址:https://www.cnblogs.com/gyc19920704/p/5442620.html
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