SqlServer类型转换函数

1、CAST（数据 as 类型）   convert（类型 ，数据）

例1：SELECT '123'+CAST('456' AS varchar)
  SELECT '123'+CONVERT(varchar,'456'）



2、convert（varchar，时间数据，标记）实现时间格式化

Select CONVERT(varchar(100), GETDATE(), 0): 05 16 2006 10:57AM

Select CONVERT(varchar(100), GETDATE(), 1): 05/16/06

Select CONVERT(varchar(100), GETDATE(), 2): 06.05.16

Select CONVERT(varchar(100), GETDATE(), 3): 16/05/06

Select CONVERT(varchar(100), GETDATE(), 4): 16.05.06

Select CONVERT(varchar(100), GETDATE(), 5): 16-05-06

Select CONVERT(varchar(100), GETDATE(), 6): 16 05 06

Select CONVERT(varchar(100), GETDATE(), 7): 05 16, 06

Select CONVERT(varchar(100), GETDATE(), 8): 10:57:46

Select CONVERT(varchar(100), GETDATE(), 9): 05 16 2006 10:57:46:827AM

Select CONVERT(varchar(100), GETDATE(), 10): 05-16-06

Select CONVERT(varchar(100), GETDATE(), 11): 06/05/16

Select CONVERT(varchar(100), GETDATE(), 12): 060516

Select CONVERT(varchar(100), GETDATE(), 13): 16 05 2006 10:57:46:937

Select CONVERT(varchar(100), GETDATE(), 14): 10:57:46:967

Select CONVERT(varchar(100), GETDATE(), 20): 2006-05-16 10:57:47

Select CONVERT(varchar(100), GETDATE(), 21): 2006-05-16 10:57:47.157

Select CONVERT(varchar(100), GETDATE(), 22): 05/16/06 10:57:47 AM

Select CONVERT(varchar(100), GETDATE(), 23): 2006-05-16

Select CONVERT(varchar(100), GETDATE(), 24): 10:57:47

Select CONVERT(varchar(100), GETDATE(), 25): 2006-05-16 10:57:47.250

Select CONVERT(varchar(100), GETDATE(), 100): 05 16 2006 10:57AM

Select CONVERT(varchar(100), GETDATE(), 101): 05/16/2006

Select CONVERT(varchar(100), GETDATE(), 102): 2006.05.16

Select CONVERT(varchar(100), GETDATE(), 103): 16/05/2006

Select CONVERT(varchar(100), GETDATE(), 104): 16.05.2006

Select CONVERT(varchar(100), GETDATE(), 105): 16-05-2006

Select CONVERT(varchar(100), GETDATE(), 106): 16 05 2006

Select CONVERT(varchar(100), GETDATE(), 107): 05 16, 2006

Select CONVERT(varchar(100), GETDATE(), 108): 10:57:49

Select CONVERT(varchar(100), GETDATE(), 109): 05 16 2006 10:57:49:437AM

Select CONVERT(varchar(100), GETDATE(), 110): 05-16-2006

Select CONVERT(varchar(100), GETDATE(), 111): 2006/05/16

Select CONVERT(varchar(100), GETDATE(), 112): 20060516

Select CONVERT(varchar(100), GETDATE(), 113): 16 05 2006 10:57:49:513

Select CONVERT(varchar(100), GETDATE(), 114): 10:57:49:547

Select CONVERT(varchar(100), GETDATE(), 120): 2006-05-16 10:57:49

Select CONVERT(varchar(100), GETDATE(), 121): 2006-05-16 10:57:49.700

Select CONVERT(varchar(100), GETDATE(), 126): 2006-05-16T10:57:49.827

Select CONVERT(varchar(100), GETDATE(), 130): 18 ???? ?????? 1427 10:57:49:907AM

Select CONVERT(varchar(100), GETDATE(), 131): 18/04/1427 10:57:49:920AM

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

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|09/15/2001

style数字在转换时间时的含义如下:

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Style(2位表示年份)    |   Style(4位表示年份)    |    输入输出格式                                    

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0                                | 100                            |    mon dd yyyy hh:miAM(或PM)              

------------------------------------------------------------------------------------------------------------

1                                |   101    美国                 |    mm/dd/yy                                       

------------------------------------------------------------------------------------------------------------
2                                |   102     ANSI                |    yy-mm-dd                                        

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3                                |   103     英法                 |    dd/mm/yy                                       

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4                                |   104     德国                 |    dd.mm.yy                                        

------------------------------------------------------------------------------------------------------------
5                                |   105     意大利              |    dd-mm-yy                                        

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6                                |   106                             |    dd mon yy                                        

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7                                |   107                             |    mon dd,yy                                        

------------------------------------------------------------------------------------------------------------

8                                |   108                             |    hh:mm:ss                                         

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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)         

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21                              |    121                            |     yyyy-mm-dd hh:mi:ss:mmm(24小时制) 

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