oracle9中子查詢(xún)中時(shí)間轉(zhuǎn)換的問(wèn)題

fouter

launchtime字段是data型,格式如下:
2007-8-10 00:00:00

select id,launchtime from vir_podcast where  launchtime = to_date('2007-8-10 00:00:00','YYYY-MM-DD HH24:MI:SS') 這樣查當(dāng)然沒(méi)有問(wèn)題
現(xiàn)在我想將2007-8-10 00:00:00替換成查詢(xún)系統(tǒng)的日期減去24小時(shí),也就是24小時(shí)前
select id,launchtime from vir_podcast where  launchtime = (select sysdate - interval '24' hour from dual)當(dāng)然這樣也沒(méi)問(wèn)題,但是查不到任何結(jié)果的

select id,launchtime from vir_podcast where  launchtime = (select to_char(sysdate - interval '24' hour,'YYYY-MM-DD HH24:MI:SS') from dual)
這樣寫(xiě)就不行了,請(qǐng)教該如何解決？謝謝。

doni

1. launchtime = (sysdate - 1) 即可,不用這么復(fù)雜
2. launchtime是date型,所以等號(hào)右側(cè)也應(yīng)該是date型,不知為什么要to_char

fouter

多謝樓上的問(wèn)題已經(jīng)解決！