UPDATE test t SET t.del=1;
UPDATE test t1,(SELECT id,title,MIN(time) FROM test GROUP BY title) t2
SET t1.del=0 WHERE t1.id=t2.id
UPDATE test t1,(SELECT id,title,MIN(time) FROM test GROUP BY title) t2
SET t1.del=0 WHERE t1.id=t2.id
是的
update tab set del=1;
update tab,(select id from (select * from tab order by time desc) t group by title) tt set tab.del=0 where tab.id=tt.id;试试
标题或url相同?
如果有:
1 呵呵 http://1
2 呵呵 http://2
3 哈哈 http://2
4 哈哈 http://3要保留哪个?
保留时间最早的那个
update tab set del=1;
UPDATE test t1,(SELECT id FROM test WHERE time IN ( SELECT MIN(time) FROM test GROUP BY title)) t2
SET t1.del=0 WHERE t1.id=t2.id;试试这个