sqlite 如何限制某个表中的数据总数
发布时间:2020-12-12 20:06:05 所属栏目:百科 来源:网络整理
导读:1、定期执行: DELETE FROM table where _id NOT IN (SELECT _id from table ORDER BY insertion_date DESC LIMIT 50) 2、或者建立一个trigger: CREATE TRIGGER delete_till_50 INSERT ON _table WHEN ( select count (*) from _table ) 50 BEGIN DELETE FR
1、定期执行: DELETE FROM table where _id NOT IN (SELECT _id from table ORDER BY insertion_date DESC LIMIT 50) 2、或者建立一个trigger: CREATE TRIGGER delete_till_50 INSERT ON _table WHEN (select count(*) from _table)>50 BEGIN DELETE FROM _table WHERE _table._id IN (SELECT _table._id ORDER BY _table._id limit (select count(*) -50 from _table )); END; (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |