MySQL-SQL基础1
p.p1 { margin: 0; font: 11px Menlo; background-color: rgba(128, 128, 128, 0.5); min-height: 13px }
p.p2 { margin: 0; font: 11px Menlo; background-color: rgba(128, 128, 128, 0.5) }
span.s1 { font-variant-ligatures: no-common-ligatures }
#插入 mysql> insert into emp values('zzx1','2002-03-09','2009-04-03','2001',3,22); Query OK, 1 row affected (0.00 sec) mysql> insert into emp values('ttx2','20023-04-10','2010-03-04','2002',4,23); ERROR 1292 (22007): Incorrect date value: '20023-04-10' for column 'birth' at row 1 mysql> insert into emp values('ttx2','2023-04-10','2010-03-04','2002',4,23); Query OK, 1 row affected (0.00 sec) mysql> select * from emp; +-------+------------+------------+---------+--------+------+ | ename | birth | hirdate | sal | deptno | age1 | +-------+------------+------------+---------+--------+------+ | zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 | | zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 | | ttx2 | 2023-04-10 | 2010-03-04 | 2002.00 | 4 | 23 | +-------+------------+------------+---------+--------+------+ 3 rows in set (0.00 sec) #更新 mysql> update emp set sal=4000 where ename='ttx2'; Query OK, 1 row affected (0.00 sec) Rows matched: 1 Changed: 1 Warnings: 0 mysql> select * from emp; +-------+------------+------------+---------+--------+------+ | ename | birth | hirdate | sal | deptno | age1 | +-------+------------+------------+---------+--------+------+ | zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 | | zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 | | ttx2 | 2023-04-10 | 2010-03-04 | 4000.00 | 4 | 23 | +-------+------------+------------+---------+--------+------+ 3 rows in set (0.00 sec) mysql> select distinct deptno from emp; +--------+ | deptno | +--------+ | 1 | | 3 | | 4 | +--------+ 3 rows in set (0.01 sec) #查询 mysql> select * from emp where deptno=1; +-------+------------+------------+---------+--------+------+ | ename | birth | hirdate | sal | deptno | age1 | +-------+------------+------------+---------+--------+------+ | zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 | +-------+------------+------------+---------+--------+------+ 1 row in set (0.00 sec) mysql> select * from emp where deptno=2; Empty set (0.00 sec) mysql> select * from emp where deptno=3; +-------+------------+------------+---------+--------+------+ | ename | birth | hirdate | sal | deptno | age1 | +-------+------------+------------+---------+--------+------+ | zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 | +-------+------------+------------+---------+--------+------+ 1 row in set (0.00 sec) mysql> select * from emp order by sal; +-------+------------+------------+---------+--------+------+ | ename | birth | hirdate | sal | deptno | age1 | +-------+------------+------------+---------+--------+------+ | zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 | | zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 | | ttx2 | 2023-04-10 | 2010-03-04 | 4000.00 | 4 | 23 | +-------+------------+------------+---------+--------+------+ 3 rows in set (0.00 sec) mysql> select * from emp order by deptno; +-------+------------+------------+---------+--------+------+ | ename | birth | hirdate | sal | deptno | age1 | +-------+------------+------------+---------+--------+------+ | zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 | | zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 | | ttx2 | 2023-04-10 | 2010-03-04 | 4000.00 | 4 | 23 | +-------+------------+------------+---------+--------+------+ 3 rows in set (0.00 sec) #查询排序 mysql> select * from emp order by deptno,sal desc; +-------+------------+------------+---------+--------+------+ | ename | birth | hirdate | sal | deptno | age1 | +-------+------------+------------+---------+--------+------+ | zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 | | zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 | | ttx2 | 2023-04-10 | 2010-03-04 | 4000.00 | 4 | 23 | +-------+------------+------------+---------+--------+------+ 3 rows in set (0.00 sec) #分页查询 mysql> select * from emp order by sal limit 3; +-------+------------+------------+---------+--------+------+ | ename | birth | hirdate | sal | deptno | age1 | +-------+------------+------------+---------+--------+------+ | zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 | | zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 | | ttx2 | 2023-04-10 | 2010-03-04 | 4000.00 | 4 | 23 | +-------+------------+------------+---------+--------+------+ 3 rows in set (0.00 sec) mysql> select * from emp order by sal limit 1,3; +-------+------------+------------+---------+--------+------+ | ename | birth | hirdate | sal | deptno | age1 | +-------+------------+------------+---------+--------+------+ | zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 | | ttx2 | 2023-04-10 | 2010-03-04 | 4000.00 | 4 | 23 | +-------+------------+------------+---------+--------+------+ 2 rows in set (0.00 sec) #查询表总数 mysql> select count(1) from emp; +----------+ | count(1) | +----------+ | 3 | +----------+ 1 row in set (0.00 sec) #针对emp表进行统计deptno的个数 mysql> select deptno,count(1) from emp group by deptno; +--------+----------+ | deptno | count(1) | +--------+----------+ | 1 | 1 | | 3 | 1 | | 4 | 1 | +--------+----------+ 3 rows in set (0.00 sec) #对ename排序并计算 mysql> select ename,count(1) from emp group by ename; +-------+----------+ | ename | count(1) | +-------+----------+ | ttx2 | 1 | | zzx1 | 2 | +-------+----------+ 2 rows in set (0.00 sec) #对sal排序并计算 mysql> select sal,count(1) from emp group by sal; +---------+----------+ | sal | count(1) | +---------+----------+ | 2000.00 | 1 | | 2001.00 | 1 | | 4000.00 | 1 | +---------+----------+ 3 rows in set (0.00 sec) #对age1排序并计算 mysql> select age1,count(1) from emp group by age1; +------+----------+ | age1 | count(1) | +------+----------+ | 21 | 1 | | 22 | 1 | | 23 | 1 | +------+----------+ 3 rows in set (0.01 sec) #查看emp表结构 mysql> desc emp; +---------+---------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +---------+---------------+------+-----+---------+-------+ | ename | varchar(20) | YES | | NULL | | | birth | date | YES | | NULL | | | hirdate | date | YES | | NULL | | | sal | decimal(10,2) | YES | | NULL | | | deptno | int(2) | YES | | NULL | | | age1 | int(4) | YES | | NULL | | +---------+---------------+------+-----+---------+-------+ 6 rows in set (0.00 sec) #对birth列排序并计算 mysql> select birth,count(1) from emp group by birth; +------------+----------+ | birth | count(1) | +------------+----------+ | 2000-01-01 | 1 | | 2002-03-09 | 1 | | 2023-04-10 | 1 | +------------+----------+ 3 rows in set (0.00 sec) #对hirdate列排序并计算 mysql> select hirdate,count(1) from emp group by hirdate; +------------+----------+ | hirdate | count(1) | +------------+----------+ | 2000-01-01 | 1 | | 2009-04-03 | 1 | | 2010-03-04 | 1 | +------------+----------+ 3 rows in set (0.00 sec) #统计部门人数同时统计总人数 mysql> select deptno,count(1) from emp group by deptno with rollup; +--------+----------+ | deptno | count(1) | +--------+----------+ | 1 | 1 | | 3 | 1 | | 4 | 1 | | NULL | 3 | +--------+----------+ 4 rows in set (0.00 sec) #统计ename同时统计总人数 mysql> select ename,count(1) from emp group by ename with rollup; +-------+----------+ | ename | count(1) | +-------+----------+ | ttx2 | 1 | | zzx1 | 2 | | NULL | 3 | +-------+----------+ 3 rows in set (0.00 sec) #统计出生人数同时统计总人数 mysql> select birth,count(1) from emp group by birth with rollup; +------------+----------+ | birth | count(1) | +------------+----------+ | 2000-01-01 | 1 | | 2002-03-09 | 1 | | 2023-04-10 | 1 | | NULL | 3 | +------------+----------+ 4 rows in set (0.00 sec) #统计录用时间同时统计总人数 mysql> select hirdate,count(1) from emp group by hirdate with rollup; +------------+----------+ | hirdate | count(1) | +------------+----------+ | 2000-01-01 | 1 | | 2009-04-03 | 1 | | 2010-03-04 | 1 | | NULL | 3 | +------------+----------+ 4 rows in set (0.00 sec) #统计薪资数同时统计总人数 mysql> select sal,count(1) from emp group by sal with rollup; +---------+----------+ | sal | count(1) | +---------+----------+ | 2000.00 | 1 | | 2001.00 | 1 | | 4000.00 | 1 | | NULL | 3 | +---------+----------+ 4 rows in set (0.00 sec) #统计年龄同时统计总人数 mysql> select age1,count(1) from emp group by age1 with rollup; +------+----------+ | age1 | count(1) | +------+----------+ | 21 | 1 | | 22 | 1 | | 23 | 1 | | NULL | 3 | +------+----------+ 4 rows in set (0.00 sec) #统计部门大于0的部门 mysql> select deptno,count(1) from emp group by deptno having count(1)>0; +--------+----------+ | deptno | count(1) | +--------+----------+ | 1 | 1 | | 3 | 1 | | 4 | 1 | +--------+----------+ 3 rows in set (0.00 sec) #计算薪资总数、最高薪资、最低薪资 mysql> select sum(sal),max(sal),min(sal) from emp; +----------+----------+----------+ | sum(sal) | max(sal) | min(sal) | +----------+----------+----------+ | 8001.00 | 4000.00 | 2000.00 | +----------+----------+----------+ 1 row in set (0.00 sec) #联表查询 mysql> create table dept(deptno int(10),deptname varchar(20)); Query OK, 0 rows affected (0.01 sec) mysql> insert into dept values(1,'tech'); Query OK, 1 row affected (0.00 sec) mysql> insert into dept values(2,'sale'); Query OK, 1 row affected (0.00 sec) mysql> insert into dept values(3,'hr'); Query OK, 1 row affected (0.00 sec) mysql> select ename from emp where emp.deptno=emp.deptno; +-------+ | ename | +-------+ | zzx1 | | zzx1 | | ttx2 | +-------+ 3 rows in set (0.00 sec) #左连接查询 mysql> select ename,deptname from emp left join dept on emp.deptno=dept.deptno; +-------+----------+ | ename | deptname | +-------+----------+ | zzx1 | tech | | zzx1 | hr | | ttx2 | NULL | +-------+----------+ 3 rows in set (0.00 sec) #右连接查询 mysql> select ename,deptname from dept right join emp on dept.deptno=emp.deptno; +-------+----------+ | ename | deptname | +-------+----------+ | zzx1 | tech | | zzx1 | hr | | ttx2 | NULL | +-------+----------+ 3 rows in set (0.00 sec) mysql> select * from emp; +-------+------------+------------+---------+--------+------+ | ename | birth | hirdate | sal | deptno | age1 | +-------+------------+------------+---------+--------+------+ | zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 | | zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 | | ttx2 | 2023-04-10 | 2010-03-04 | 4000.00 | 4 | 23 | +-------+------------+------------+---------+--------+------+ 3 rows in set (0.00 sec) mysql> select * from dept; +--------+----------+ | deptno | deptname | +--------+----------+ | 1 | tech | | 2 | sale | | 3 | hr | +--------+----------+ 3 rows in set (0.01 sec) mysql> insert into dept values(4,'sl'); Query OK, 1 row affected (0.00 sec) mysql> insert into emp values('ssss','2019-01-01','2018-01-01',5000,2,24); Query OK, 1 row affected (0.00 sec) mysql> select * from dept; +--------+----------+ | deptno | deptname | +--------+----------+ | 1 | tech | | 2 | sale | | 3 | hr | | 4 | sl | +--------+----------+ 4 rows in set (0.00 sec) mysql> select * from emp; +-------+------------+------------+---------+--------+------+ | ename | birth | hirdate | sal | deptno | age1 | +-------+------------+------------+---------+--------+------+ | zzx1 | 2000-01-01 | 2000-01-01 | 2000.00 | 1 | 21 | | zzx1 | 2002-03-09 | 2009-04-03 | 2001.00 | 3 | 22 | | ttx2 | 2023-04-10 | 2010-03-04 | 4000.00 | 4 | 23 | | ssss | 2019-01-01 | 2018-01-01 | 5000.00 | 2 | 24 | +-------+------------+------------+---------+--------+------+ 4 rows in set (0.00 sec) mysql> select ename,deptname from emp left join dept on emp.deptno=dept.deptno; +-------+----------+ | ename | deptname | +-------+----------+ | zzx1 | tech | | ssss | sale | | zzx1 | hr | | ttx2 | sl | +-------+----------+ 4 rows in set (0.00 sec) mysql> select ename,deptname from dept right join emp on dept.deptno=emp.deptno; +-------+----------+ | ename | deptname | +-------+----------+ | zzx1 | tech | | ssss | sale | | zzx1 | hr | | ttx2 | sl | +-------+----------+ 4 rows in set (0.00 sec)
MySQL-SQL基础1的更多相关文章
- 2.Mysql SQL基础
2.Mysql SQL基础2.1 SQL简介 SQL(Structure Query Language)是结构化查询语言.2.2 SQL使用入门 2.2.1 SQL分类 SQL分为DDL.DML(DQ ...
- 3 MySQL SQL基础
目录 1. SQL概述2. 数据库操作3. 表操作4. 记录操作 1. SQL概述 SQL,结构化查询语言(Structured Query Language),一种数据库查询和程序设计语言,用于存取 ...
- mysql sql 基础总结
1 mysql top n使用 select * from table limit n; 2 统配符使用必须和like结合使用 like % 通配符 描述 % 替代一个或多个字符 _ 仅替代一个 ...
- mysql使用基础 sql语句(一)
csdn博文地址:mysql使用基础 sql语句(一) 点击进入 命令行输入mysql -u root -p,回车再输入密码,进入mysql. 终端命令以分号作为一条语句的结束,可分为多行输入,只需 ...
- MySQL基础整理(一)之SQL基础(未完成)
大家好,我是浅墨竹染,以下是MySQL基础整理(一)之SQL基础 1.SQL简介 SQL(Structure Query Language)是一种结构化查询语言,是使用关系模型的数据库应用语言. 2. ...
- ASP.NET实现二维码 ASP.Net上传文件 SQL基础语法 C# 动态创建数据库三(MySQL) Net Core 实现谷歌翻译ApI 免费版 C#发布和调试WebService ajax调用WebService实现数据库操作 C# 实体类转json数据过滤掉字段为null的字段
ASP.NET实现二维码 using System;using System.Collections.Generic;using System.Drawing;using System.Linq;us ...
- sql 基础练习 计算7天各个时间点的总和 group by order mysql一次查询多个表
SQL 基础练习 -- 创建数据库 CREATE DATABASE school CHARACTER SET UTF8; -- 使用数据库 USE school; -- id: 学生的id -- na ...
- (2.16)Mysql之SQL基础——函数
(2.16)Mysql之SQL基础——函数 关键词:mysql函数,mysql自定义函数,mysql聚合函数,mysql字符串函数,mysql数值函数 1.自定义函数 -- (1)一般形式 creat ...
- (2.15)Mysql之SQL基础——开发设计最佳规范
(2.15)Mysql之SQL基础——开发设计最佳规范 关键字:mysql三大范式,mysql sql开发规范 分析: show profile.mysqllsla.mysqldrmpslow.exp ...
- (2.14)Mysql之SQL基础——游标
(2.14)Mysql之SQL基础——游标 关键词:Mysql游标 -- (1)定义游标 declare cur_name cursor for select * from table_name wh ...
随机推荐
- tomcat日志详解
1 tomcat 日志详解 1.1 tomcat 日志配置文件 tomcat 对应日志的配置文件:tomcat目录下的/conf/logging.properties. tomcat 的日志等级有:日 ...
- 构建前端第4篇之---使用css用法 height
张艳涛 写于2021-1-20 height: 100%; What: html的元素标签,例如 <html>,<body>,<div>都有height的css属 ...
- ifix重用性模块化开发纪实(以污水处理泵站为例)
在经过多个自动化上位机的开发后,对上位机的重用开发和提高效率,减少重复工作有了一定的积累.故而产生了模块化建设上位机的思路.现从当下项目开始,研究出一套可重复利用的模块化系统. 1.点表整理 从PLC ...
- raven靶机
仅供个人娱乐 靶机信息 Raven 下载地址:https://www.vulnhub.com/entry/raven-1,256/ 一.主机探测 端口信息 目录扫描 80端口 根据页面开始搜寻有用的信 ...
- SpringBoot - Bean validation 参数校验
目录 前言 常见注解 参数校验的应用 依赖 简单的参数校验示例 级联校验 @Validated 与 @Valid 自定义校验注解 前言 后台开发中对参数的校验是不可缺少的一个环节,为了解决如何优雅的对 ...
- MSF+Nmap TCP空闲扫描
MSF+Nmap TCP空闲扫描 前言 TCP空闲扫描是一种高级的扫描技术,可以冒充内网中另一台IP地址来对内网中的目标进行隐秘的扫描. 正文 在进行扫描之前,我们需要了解一个概念,即递增IP帧标识, ...
- Windows协议 NTLM篇
NTLM 基础 介绍 LM Hash & NTLM Hash Windows本身是不会存储明文密码的,只保存密码的hash 其中本机用户的密码hash是放在本地的SAM文件里面,域内用户的密码 ...
- 得到、微信、美团、爱奇艺APP组件化架构实践
一.背景 随着项目逐渐扩展,业务功能越来越多,代码量越来越多,开发人员数量也越来越多.此过程中,你是否有过以下烦恼? 项目模块多且复杂,编译一次要5分钟甚至10分钟?太慢不能忍? 改了一行代码 或只调 ...
- 揭秘阿里云 RTS SDK 是如何实现直播降低延迟和卡顿
作者:予涛 途坦 这个夏天,没什么能够比一场酣畅淋漓的奥运比赛来的过瘾.但是,在视频平台直播观看比赛也有痛点:"卡顿" 和 "延时".受限于不同地域.复杂的网络 ...
- 【学习笔记】Expression表达式目录树
Expression表达式目录树:一个能拼装能解析的数据结构,语法树. 一.手动拼装表达式目录树 示例1: /// <summary> /// 展示表达式树,协助用的 /// 编译lamb ...