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sql server与oracle 获取时间与日期区别
1.获取系统当前时间
sql server 2005: 

select getdate()

getdate() 函数从 sql server 返回当前的时间和日期。

语法
getdate()实例
例子 1
使用下面的 select 语句:

select getdate() as currentdatetime结果:

currentdatetime
2008-12-29 16:25:46.635


oracle:
 

select sysdate from dual

 
39 select to_char(sysdate,"dd") from dual;                     -- 20  
40 select to_char(sysdate,"d") from dual;                      -- 5  
41 select to_char(sysdate,"ddd") from dual;                    -- 263  
42 select to_char(sysdate,"ww") from dual;                     -- 38  
43 select to_char(sysdate,"w") from dual;                      -- 3  
44 select to_char(sysdate,"yyyy/mm/dd hh24:mi:ss") from dual;  -- 2007/09/20 15:24:13  
45 select to_char(sysdate,"yyyy/mm/dd hh:mi:ss") from dual;    -- 2007/09/20 03:25:23  
46 select to_char(sysdate,"j") from dual;                      -- 2454364  
47 select to_char(sysdate,"rr/mm/dd") from dual;               -- 07/09/20 


2.获取年月日

sql server 2005:
代码如下:

select year(getdate()) --2011
select month(getdate()) --3
select day(getdate()) --23

oracle:
代码如下:

select to_char(sysdate,"yyyy") from dual --2011
select to_char(sysdate,"mm") from dual --03
select to_char(sysdate,"dd") from dual --23
 select to_char(sysdate,"yyyy/mm/dd") from dual;             -- 2007/09/20  
35 select to_char(sysdate,"yyyy") from dual;                   -- 2007  
36 select to_char(sysdate,"yyy") from dual;                    -- 007  
37 select to_char(sysdate,"yy") from dual;                     -- 07  
38 select to_char(sysdate,"mm") from dual;                     -- 09


q 季度
hh 小时(12)
hh24 小时(24)
mi 分
ss 秒
d 周中的星期几

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