转载源:http://www.jb51.net/article/42613.htm SQL按照日.周.月.季度.年统计数据的方法 方式一: --按日 select sum(consume),day([date]) from consume_record where year([date]) = '2006' group by day([date]) --按周quarter select sum(consume),datename(week,[date]) from consume_record…
原文:[SQL Server性能优化]删除大量数据的方法比较 如果你要删除表中的大量数据,这个大量一般是指删除大于10%的记录,那么如何删除,效率才会比较高呢? 而如何删除才会对系统的影响相对较小呢? 下面先做一个实验,然后对这个实验的结果进行分析,然后得出结论. 1.创建数据库 use master go if exists(select * from sys.databases where name = 'test') drop database test go create databas…
pg数据库按周,月统计数据 SELECT date_trunc('WEEK', insert_time) as insertDate, SUM(data_increment) as dataTotal,SUM(human_increment) as humanTotal from human_data_sum t where t.idtype=? GROUP BY insertDate ORDER BY insertDate DESC SELECT date_trunc('MONTH', ins…
一.mysql按日统计 ) count ' and start_time > '2017-06-28' group by days; 二.mysql按周统计 ) ' group by weeks; 三.mysql按月统计 ) ' group by months; 四.方便的场景 这对于数据量不大的表非常有效. 如:按月统计某员工的迟到情况啦等等. 五.大量的数据 例如每天产生20W数据,执行这个按天统计一年是很夸张的事情. 我能想到的办法就是: [分时统计] 1. 历史数据是不变的 2. 指定时…
知识关键词:DATE_FORMAT 按天统计: SELECT DATE_FORMAT(create_time,'%Y%m%d') days, COUNT(caseid) count FROM tc_case GROUP BY days; 按周统计: SELECT DATE_FORMAT(start_time,'%Y%u') weeks, COUNT(product_no) count FROM test GROUP BY weeks; 按月统计: SELECT DATE_FORMAT(start…
知识关键词:DATE_FORMAT select DATE_FORMAT(create_time,'%Y%u') weeks,count(caseid) count from tc_case group by weeks; select DATE_FORMAT(create_time,'%Y%m%d') days,count(caseid) count from tc_case group by days; select DATE_FORMAT(create_time,'%Y%m') month…
知识关键词:DATE_FORMAT select DATE_FORMAT(create_time,'%Y%u') weeks,count(caseid) count from tc_case group by weeks; select DATE_FORMAT(create_time,'%Y%m%d') days,count(caseid) count from tc_case group by days; select DATE_FORMAT(create_time,'%Y%m')…