create database test
default character set uft8;
show databases;
use test;
create table student(
sno char(9) primary key,
sname char(20),
ssex char(2),
sage smallint,
sdept char(40),
saddr char(100)
);
select * from student
insert intostudent(sno,sname,ssex,sage,sdept,saddr)
values('2022308097','李珊珊','女',18,'jk','b209'),
insert intostudent(sno,sname,ssex,sage,sdept,saddr)
values
('2022308093','陈政怡','女',18,'ps','b209'),
('2022308095','曹馨月','女',18,'ks','b209'),
('2022308099','覃雅思','女',18,'dy','b209'),
select * from student;
selct *
from student
where sdept='dy'selectcount(*)
from student;
update student
set sage=sage-1where sname=‘李珊珊’;
delete
from test
where grade isnull;