zoukankan      html  css  js  c++  java
  • 排序,去重,分组,作业

    all:所有的意思
    in:代表在某些参数范围之内的都符合条件【in()】括号里面写参数,相当于多个OR
    select *from 文件名 where 表名 in ()
    not:起到修饰的作用,取反,写在in前面
    select *from 文件名 where 表名 not in ()
    between and 表示在某个范围之内,相当于>= <=
    select *from 文件名 where ids>500 and ids<505
    select *from 文件名 where ids between 500 and 505
    模糊查询,行业里面带国家两个字
    select *from 文件名 where name like'%国家%'
    select *from 文件名 where name like'国家'
    select *from 文件名 where name like'%机构'
    select *from 文件名 where name not like'%国家%'


    select *from 文件名 where ids > all
    (
    select ids from 文件名 where ids >1190 and ids <1995

    )
    any:大于小的,小于大的(大于里面的一个)
    查出一列来当做参数来使用


    怎么排序
    --select *from 文件名 order by ids表里面的列
    asc:升序的意思
    desc:从大往小排
    对两列进行排序
    select *from 文件名 order by parent,ids
    parent,ids:为列名

    分组:把一列里面相同的分为一组
    select  列名 from 文件名 group by 列名
    select code from 文件名 where parent='m'


    去重
    select distinct parent from category
    前多少条数据
    select top 5 *from category
    select top 5 *from category order by ids
    select top 5 *from dategory where ids>900 and ids<950 order by ids


    --学生信息表
    --学号,姓名,班级,性别,教师,出生日期,身高
    添加20条虚拟数据
    查询男同学身高170以上的
    查询姓王的同学信息
    查询一共有几个班级
    查询女同学里身高在168,170,172折三个数的信息
    create table xueshengxinxibiao

         xuehao int,
         name  varchar(50),
         class varchar(50),
         xingbie varchar(50),
         jiaoshi varchar(50),
         chushengriqi varchar(50),
         shengao varchar(50)
    )
    insert into xueshengxinxibiao values(1,'乔峰','一年级一班','男','天龙','1988-03-14','181cm')
    insert into xueshengxinxibiao values(2,'阿朱','一年级一班','女','天龙','1988-04-05','168cm')
    insert into xueshengxinxibiao values(3,'段誉','一年级一班','男','天龙','1988-12-09','178cm')
    insert into xueshengxinxibiao values(4,'王语嫣','一年级一班','女','天龙','1988-05-06','173cm')
    insert into xueshengxinxibiao values(5,'虚竹','一年级一班','男','天龙','1988-06-04','178cm')
    insert into xueshengxinxibiao values(6,'梦姑','一年级一班','女','天龙','1988-07-19','172cm')
    insert into xueshengxinxibiao values(7,'慕容复','一年级一班','男','天龙','1988-12-18','175cm')
    insert into xueshengxinxibiao values(8,'阿碧','一年级一班','女','天龙','1988-09-01','165cm')
    insert into xueshengxinxibiao values(9,'王夫人','一年级一班','女','天龙','1988-08-08','165cm')
    insert into xueshengxinxibiao values(10,'钟灵','一年级一班','女','天龙','1988-06-01','160cm')
    insert into xueshengxinxibiao values(11,'段正淳','一年级一班','男','天龙','1988-03-04','176cm')
    insert into xueshengxinxibiao values(12,'杨过','一年级二班','男','神雕','1988-10-01','180cm')
    insert into xueshengxinxibiao values(13,'时迁','一年级三班','男','水浒','1988-09-25','170cm')
    insert into xueshengxinxibiao values(14,'宋江','一年级三班','男','水浒','1988-05-23','173cm')
    insert into xueshengxinxibiao values(15,'林冲','一年级三班','男','水浒','1988-11-11','183cm')
    insert into xueshengxinxibiao values(16,'孙二娘','一年级三班','女','水浒','1988-02-18','174cm')
    insert into xueshengxinxibiao values(17,'小龙女','一年级二班','女','神雕','1988-06-19','168cm')
    insert into xueshengxinxibiao values(18,'王蓉','一年级二班','女','神雕','1988-08-23','165cm')
    insert into xueshengxinxibiao values(19,'郭靖','一年级二班','男','神雕','1988-08-13','175cm')
    insert into xueshengxinxibiao values(20,'洪七公','一年级二班','男','神雕','1988-08-29','170cm')
    select *from xueshengxinxibiao
    select *from xueshengxinxibiao where xingbie='男'and shengao > '170cm'
    select *from xueshengxinxibiao where name like '%王%'
    select class from xueshengxinxibiao group by class
    select *from xueshengxinxibiao where xingbie='女'and (shengao ='168cm'or shengao='170cm'or shengao='172cm')
    --查男同学的身高高于所有女同学的同学信息
    select top 3 *from xueshengxinxibiao where shengao not in (select top 5 shengao from xueshengxinxibiao order by shengao desc,xuehao desc) order by shengao desc

    --查男同学的身高高于所有女同学的同学信息
    select *from xueshengxinxibiao where xingbie='男' and shengao>all(select shengao from xueshengxinxibiao where xingbie='女')

  • 相关阅读:
    EventHandler 与常见的.Net预定义委托
    Consistent Hashing算法及相关技术
    全序, 分布式一致性的本质
    Paxos Made Simple
    Strong Consistency, 强一致性技术概述
    Chubby lock service for looselycoupled distributed systems
    AntiEntropy Protocols
    Mesos: A Platform for FineGrained Resource Sharing in the Data Center
    Spark A FaultTolerant Abstraction for InMemory Cluster Computing
    Vector Clocks, 时间向量
  • 原文地址:https://www.cnblogs.com/liuyuwen900326/p/4120161.html
Copyright © 2011-2022 走看看