简单常用的sql,统计语句,陆续整理添加吧
1. 分段统计分数
if object_id('[score]') is not null drop table [score] go create table [score]([学号] int,[课程编号] varchar(8),[成绩] int) insert [score] select 2006091001,'04010101',75 union all select 2006091001,'04010102',84 union all select 2006091001,'04010103',68 union all select 2006091001,'04010104',68 union all select 2006091002,'04010101',86 union all select 2006091002,'04010102',90 union all select 2006091002,'04010103',67 union all select 2006091003,'04010101',74 union all select 2006091003,'04010102',45 union all select 2006091004,'04010101',72 union all select 2006091005,'04010101',56 ---查询--- select 课程编号, [80分上]=sum(case when 成绩>=80 then 1 else 0 end), [80分下]=sum(case when 成绩<80 then 1 else 0 end), [合计]=count(1) from score group by 课程编号 ---结果--- 课程编号 80分上 80分下 合计 -------- ----------- ----------- ----------- 04010101 1 4 5 04010102 2 1 3 04010103 0 2 2 04010104 0 1 1 (所影响的行数为 4 行)
2. 查询,删除重复数据
查询: select * from admin a , ( SELECT b.password,b.reallyname FROM [db_Blog].[dbo].[Admin] b group by password,reallyname having count(*)>1 ) b where a.password=b.password and a.reallyname=b.reallyname 删除: delete from admin where id in ( select min(id) from admin group by userName,password having count(*)>1)
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