mysql常用查询语句笔记

统计部分：

按周： select DATE_FORMAT(create_time,'%Y%u') weeks,count(caseid) count from tc_casegroup by weeks;

按日： select DATE_FORMAT(create_time,'%Y%m%d') days,count(caseid) count from tc_casegroup by days;

按月： select DATE_FORMAT(create_time,'%Y%m') months,count(caseid) count from tc_casegroup by months;

去重计算总数

select count(distinct(过滤字段)) from table where ...;