在sql server裏可以使用:
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中沒有定義和sql server中一樣的DateAdd函數,
oracle可以通過interval 'n' year/month/day/hour/minute/second/second(p,s)
的方式來增減時間
下面是自己在oracle中寫的DateAdd函數
函數調用基本同sql server一樣, 不過datepart部分需要以字符串的方式輸入, 即
DateAdd(d,1,to_date('2005-12-09','yyyy-mm-dd'))
要改為
DateAdd('d',1,to_date('2005-12-09','yyyy-mm-dd'))
函數定義如下函數中的註釋是datepart的新説明, 與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