brnd.net
相关文档
当前位置:首页 >> hAving Count >>

hAving Count

对由sum、count或其它集合函数运算结果的输出进行限制 having count(学号)指的是 学生数目( 大于等于)数值 create TABLE Table1 ( ID int identity(1,1) primary key NOT NULL, classid int, sex varchar(10), age int, ) --添加测试数据 In...

select id, count(*) from table a where ... group by id having count(*)>2 -- 以id分组统计,查询分组后数量大于2的id和数量。

出现了having说明用到了聚合函数,having用来约束聚合后的内容,举个例子 selelct id,sum(value) from table where id > 5 group by value having count(value)>3 where只能约束id>5的行,但是之后结果被聚合,行被合并,where就没用了,我们要...

--1,查询hm有重复的记录select hm,count(*) from a group by hm having count(*)>1--2,查询hm和xm都有重复select hm,xm count(*) from a group by hm,xm having count(*)>1

譬如如下数据 id value 1 2 1 3 2 3 3 5 3 6 可以写个语句统计value的分组 select id,sum(value) from table group by id having sum(value)>=5 这样的结果就是 1 5 3 11 其实这句的意思就是 select id,sum(value) from table where sum(value)>...

做法:select * from user_num group by user HAVING sum(num)>10 ; 注意:一个HAVING子句最多只能包含40个表达式,HAVING子句的表达式之间可以用AND和OR分割。

61=C或D 62=C SELECT Sno , AVG(Grade) FROM SC GROUP BY Sno HAVING COUNT(Sno)>1;

加个where 条件不行么,where status 0 如果不行的话,就写子查询, 先筛选where status 0 再group by

例如:检索指定班级编号的班级中重名的学生姓名select student_name from student where class_number = '班级编号' group by student_name having count(student_name) >= 2

select a,count(*) from table group by a having count(*)>1 嗯。是的。这样是查出来该字段重复2次以上的列。

网站首页 | 网站地图
All rights reserved Powered by www.brnd.net
copyright ©right 2010-2021。
内容来自网络,如有侵犯请联系客服。zhit325@qq.com