Query SQL statements and delete duplicate records

1, the lookup table excess <wiz_tmp_highlight_tag class = "cm-searching"> repeatedly recorded, <wiz_tmp_highlight_tag class = "cm-searching"> repeatedly recorded is judged based on a single field (Id)

 

select * from 表 where Id in (select Id from 表 group by Id having count(Id) > 1)

 

2, the table remove excess <wiz_tmp_highlight_tag class = "cm-searching"> repeatedly recorded, <wiz_tmp_highlight_tag class = "cm-searching"> repeatedly recorded is judged based on a single field (Id), leaving only the smallest recording rowid

 

DELETE from 表 WHERE (id) IN ( SELECT id FROM 表 GROUP BY id HAVING COUNT(id) > 1) AND ROWID NOT IN (SELECT MIN(ROWID) FROM 表 GROUP BY id HAVING COUNT(*) > 1);

 

3, to find the excess <wiz_tmp_highlight_tag class = "cm-searching"> recorded repeatedly (multiple fields) in the table

 

select * from 表 a where (a.Id,a.seq) in(select Id,seq from 表 group by Id,seq having count(*) > 1)

 

4, the table remove excess <wiz_tmp_highlight_tag class = "cm-searching"> recorded repeatedly (more than one field), leaving only the smallest recording rowid

 

delete from 表 a where (a.Id,a.seq) in (select Id,seq from 表 group by Id,seq having count(*) > 1) and rowid not in (select min(rowid) from 表 group by Id,seq having count(*)>1)

 

5, find excess <wiz_tmp_highlight_tag class = "cm-searching"> recorded repeatedly (multiple fields) in the table does not include the smallest recording rowid

 

select * from 表 a where (a.Id,a.seq) in (select Id,seq from 表 group by Id,seq having count(*) > 1) and rowid not in (select min(rowid) from 表 group by Id,seq having count(*)>1)

来源： <http://www.cnblogs.com/252e/archive/2012/09/13/2682817.html>