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--這樣試下呢?
delete tbl_survey
where not exists (select 1 from (select max(n_id) n_id from tbl_survey group by n_human_id) t
where tbl_survey.n_id=t.n_id);
--利用rowid,实现高效删除:
delete from tbl_survey a where a.rowid > (select min(b.rowid) from tbl_survey b where b.n_id = a.n_id);
delete from tbl_survey a where a.rowid < (select min(b.rowid) from tbl_survey b where b.n_id = a.n_id);
delete from tbl_survey a where a.rowid <> (select min(b.rowid) from tbl_survey b where b.n_id = a.n_id);
--删除重复数据的三种写法:
delete from tbl_survey where n_id > (select min(n_id) from tbl_survey);
delete from tbl_survey where n_id < (select max(n_id) from tbl_survey);
delete from tbl_survey where n_id <> (select max(n_id) from tbl_survey);