在sql server里可以使用：

where start_date <=

DateAdd(d,1,to_date('2005-12-09','yyyy-mm-dd'))

and completion_date >=

to_date('2005-12-09', 'yyyy-mm-dd') ；oracle中没有定义和sql server中一样的DateAdd函数,

oracle可以通过interval 'n' year/month/day/hour/minute/second/second(p,s)

的方式来增减时间

下面是在oracle中写的DateAdd函数

函数调用基本同sql server一样, 不过datepart部分需要以字符串的方式输入, 即

DateAdd(d,1,to_date('2005-12-09','yyyy-mm-dd'))

要改为

DateAdd('d',1,to_date('2005-12-09','yyyy-mm-dd'))

函数定义如下函数中的注释是datepart的新说明, 与sql server中的略有不同)

create or replace function DATEADD( datepart varchar2, num number, indate date ) return date is

Result date;

v_sql varchar2(1000);

v_datepart varchar2(30);

v_ms varchar2(13);

begin

v_datepart := lower(datepart);

/*

Datepart Abbreviations

year yy, y

quarter qq, q

month mm, m

day dd, d

week wk, w

hour hh, h

minute mi, n

second ss, s

millisecond ms

*/

case

when v_datepart in ('year','yy','y') then

v_sql := 'select :1 + interval '''||num||''' year from dual';

when v_datepart in ('quarter','qq','q') then

v_sql := 'select :1 + (interval ''3'' month) * '||num||' from dual';

when v_datepart in ('month','mm','m') then

v_sql := 'select :1 + interval '''||num||''' month from dual';

when v_datepart in ('week','wk','w') then

v_sql := 'select :1 + (interval ''7'' day) * '||num||' from dual';

when v_datepart in ('day','dd','d') then

v_sql := 'select :1 + interval '''||num||''' day from dual';

when v_datepart in ('hour','hh') then

v_sql := 'select :1 + interval '''||num||''' hour from dual';

when v_datepart in ('minute','mi','n') then

v_sql := 'select :1 + interval '''||num||''' minute from dual';

when v_datepart in ('second','ss','s') then

v_sql := 'select :1 + interval '''||num||''' second from dual';

when v_datepart in ('millisecond','ms') then

v_ms := to_char(num/1000,'fm999999990.000');

v_sql := 'select :1 + interval '''||v_ms||''' second(9,3) from dual';

else

RAISE_APPLICATION_ERROR(-20001, ''''||datepart||''' is not a recognized dateadd option.' );

end case;

execute immediate v_sql into Result using indate;

return(Result);

EXCEPTION

WHEN OTHERS THEN

RAISE ;

end DATEADD;

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