問題：
在BBS中，content 和? review 兩張表，其中content 記錄的是 帖子信息（topic_id,topic_title,topic_content等字段），review 表中記錄的是回帖的信息，(review_id,topic_id等字段)在 求一SQL語句，其中topic_id和review_id都是自動增加，現在要求查詢出有最新回復的帖子的信息，同時要求有多個回復的一個帖子的主題只能顯示一次，能用一個SQL語句搞定嗎？數據庫是MYSQL 求高手指點下

回答：
select t.id,t.title,t.content,r.newposttime from topic as t inner join (select max(posttime) as newposttime, topicid from review group by topicid) as r on t.id=r.topicid
?
//測試
create table topic(
? id int primary key identity(1,1),
? title varchar(128),
? content text
)

insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')
insert into topic(title,content) values('title1','content1')

create table review(
? id int primary key identity(1,1),
? topicid int references topic(id),
? content text,
? posttime datetime default getdate()
)

insert into review(topicid,content) values(1,'reice1')
insert into review(topicid,content) values(1,'reice1')
insert into review(topicid,content) values(2,'reice1')
insert into review(topicid,content) values(2,'reice1')
insert into review(topicid,content) values(2,'reice1')
insert into review(topicid,content) values(3,'reice1')
insert into review(topicid,content) values(3,'reice1')
insert into review(topicid,content) values(3,'reice1')
insert into review(topicid,content) values(3,'reice1')
insert into review(topicid,content) values(4,'reice1')

select t.id,t.title,t.content,r.newposttime from topic as t inner join (select max(posttime) as newposttime, topicid from review group by topicid) as r on t.id=r.topicid

這些是測試數據,sqlserver2000測試通過