不是DB不常查询使用,偶尔要用记录备忘

字段重复次数查询

select humanId,count(*) from demo_achieve_7_day group by humanId having count(humanId)>1;

实测这个更快,快20-40%

select humanId,count(*) as c from demo_achieve_7_day group by humanId having c>1;

查询中文

加个N,不懂原理百度不到,群友说什么存储类型Nvarchar

set character_set_results=utf8;select * from user where name like N'%微凉%';"