如何在sql语句中查询字段date中所示时间距今一个月内的数据?(50分)

sigh,编来编去的越编越糊涂了
此处先谢过了

select * from yourtable where (month(date)-month(yourdatefield)=1 and
year(date)=year(yourdatefield) ) or (month(date)=1 and month(yourdatefield)=12 and
year(date)-year(yourdatefield)=1)

select * from yourtable where :udate-udatefield<=30
query.parambyname('udate').asdatetime:=strtodatetime(edit1.text);

设TheDate为日期型字段

Var
NowDate:TDateTime;
LastDate:TDateTime;
...
NowDate:=? //自己设定 strtodatetime('19999-5-7');
LastDate:=NowDate-30 //

Query.close;
Query.SQL:=' Select * from UTable
where (TheDate>:LastDate) and (TheDate<=:NowDate)'
Query.ParamByName('LastDate').AsDatetime:=LastDate;
Query.ParamByName('NowDate').AsDatetime:=NowDate;
Query.Open;
...

OK!

试了你们两个的解法，怎么好象都有问题？
To:g622
你的month(date)的用法好象不承认？
To:Hjking
呵呵，你的udate和udatefield把我都搞晕了
我觉得这里的udatefield是不是应该采用系统的日期？
而udate是数据库本身有的，也用不着从edit里读的...

多人接受答案了。