随便写的sql语句数据库

随便写的简单的sql语句，贴上来便于以后回顾

mysql -uroot -p; #输入密码，登录数据库show databases; #查看所有数据库create database zqs_db character set utf8; #创建数据库并设置编码为utf8use zqs_db; #选择数据库show tables; #查看当前数据库中所有的数据表#创建数据表 create table student( id int unsigned not null auto_increment primary key, name char(8) not null, sex enum('男','女') not null default '男', age tinyint unsigned not null, tek char(13) not null default '-' #foreign key(classid) references class(id); #创建外键 ); #插入数据（全部字段） insert into student values(null,'张三','男',21,15212344321); #插入部分数据 insert into student (name) values('周一'); #查询数据 select * from student where age>18 and sex='男'; #删除数据 delete from student where age<18 and tel = '-'; #添加字段 alter table student add address char(60) not null after id; #删除字段 alter table student drop address; #修改字段名称 alter table student change tek tel char(13) not null default '-'; #explain select * from student; #show status; #show status like 'uptime'; #当前mysql 运行时间 #show status like 'connections'; #查看数据库的链接数量 #show status like 'slow_queries'; #显示慢查询 #set long_query_time=2; #即修改慢查询时间为2秒 #show variables like 'long_query_time'; #create index name_indexon student(name); #创建普通索引 #explain select name from student; #create unique index id_un on student(id); #创建为一索引 #explain select * from student where id>1; #create fulltext index address_ft on student(name); #创建全文索引 #explain select * from student where match(name)against('周一'); #show index from student; #查看指定表的全部索引 #show keys from student; #查看指定表的全部索引 select id,sex,avg(age) as age_avg,sum(age) as age_sum,count(*) as count from student where id>1#where 必须出现在group by前 group by sex having age_sum >100; #having 必须出现在 group by 后

【随便写的sql语句】