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
- 🏆【Java技术专区】「并发编程专题」教你如何使用异步神器CompletableFuture
前提概要 在java8以前,我们使用java的多线程编程,一般是通过Runnable中的run方法来完成,这种方式,有个很明显的缺点,就是,没有返回值.这时候,大家可能会去尝试使用Callable中的 ...
- 比@EnableMongoAuditing功能强大的实现
问题出现 以前通过@EnableMongoAuditing.@CreateDate.@LastModifiedDate进行实体类创建时间.修改时间的自动管理. 但为了实现多数据源的管理以及切换,自己覆 ...
- docker版LAMP(PHP+MYSQL+APACHE)配置
最近在搭测试环境,一开始就在vagant和docker之间来回折腾.两者其实都非常适合用来搭开发环境:但最终让我决定用Docker的原因是因为Vagant在hyper-v下出现了一些奇怪的问题,所以D ...
- shell中cmd1 && cmd2 || cmd3的含义
在某些情况下,很多指令我想要一次输入去执行,而不想要分次去执行时,就要用到 && || 了.cmd 1 && cmd21,若cmd1执行完毕之后且正确执行($?=0), ...
- Javac 编译器
编译过程 Javac 编译过程大致可以分为1个准备过程和3个处理过程: 准备过程:初始化插入式注解处理器. 解析与填充符号表过程,包括: 词法.语法分析,将源代码的字符流转变为标记集合,构造出抽象语法 ...
- PAT甲级 1112 Stucked Keyboard
题目链接:https://pintia.cn/problem-sets/994805342720868352/problems/994805357933608960 这道题初次写的时候,思路也就是考虑 ...
- PDL语言/ 盒图N-S/ PAD图
PDL语言 伪码伪代码 基本语法 算法用Begin开始,以End结束(如果只表示中间部分的算法可以不要) 每一条指令,占一行.指令的结束不用任何符号 注释 用"//"表示 用Pri ...
- Tengine2.3+openssl1.1.1支持TLS1.3
安装包下载: openssl1.1.1 链接:https://pan.baidu.com/s/1-qCDhkLtlkT0fdwKdVuh2g 提取码:0ncc pcre3.2.1 链接:https:/ ...
- Linux系统CPU信息查询方法
lscpu cat /proc/cpuinfo对绝大多数Linux适用,lscpu更简练 cat /proc/cpuinfo 下面是一个实例: processor : 0 vendor_id : Ge ...
- Use iTunes on Linux
Today I installed iTunes (Windows installer) via wine. But after installation it didn't work. Then I ...