SQL语句
- 查询
select ··
from ··
where··
like··
between ·· and ··
as
- 条件查询
and=“并”集合
or=“或”集合
in=“在···范围内”
##根据课程代号（code）查找所有可选的课程设置
SELECT
co.id 'course_id',
co.code 'course_code',
co.name 'course_name',
co.description 'course_description',
co.credit 'course_credir',
ct.id 'course_template_id',
ct.course_type_id ,
ct.create_datetime,
cf.id 'course_offered_id',
cf.class_capacity,
cf.class_remain,
cf.class_time
FROM
course_template ct,
course co,
course_offered cf
WHERE
cf.course_template_id = ct.id
AND ct.course_id = co.id
AND co.code = '数据库'
and cf.class_remain >0;
- 插入语句
Insert into table( ···)
vlaues（）
insert into student(id,firstname,lastname,phone,email,gender,age,student_status_id,accommodation_id,sid)values(2,'萧','燚','15705799575','xy@sina.com','男',19,1,2,102);
- 更新语句
update （table···）
set ···
where ···
禁用安全更新
set sql_safe_updates =0;
开启安全更新
set sql_safe_updates =1;
set sql_safe_updates=0;
UPDATE student
SET
student_status_id = 1
WHERE
gender = '男';
UPDATE teacher t
SET
t.firstname = '栗子',
t.lastname = '西'
WHERE
t.id = 4;
set sql_safe_updates=1;
- 排序
order by （用于对结果排序）··· desc 降序
order by （用于对结果排序）··· asc 升序
select* from student order by age asc;
select* from student order by sid desc;
