增：insert into t_1（name,age） values （’李小争’23）;
values 中顺序要和表名中的顺序一致
查：select name,id from t1;
select * from t1;//查询出所有字段
select * from t_student where age
删：delete from t_student where
从t_student中删除name字段等于lxz的数据
delete from t_student
删除t_student中的所有数据
delete from t_student where age>100 or name=’lxz’ 或者
delete from t_student where age>100 and height>150 并且
更新：update t_student set age=age+1
update t_student set height=180
update t_student set love='散步' where age>100
select name as 姓名, age as 年龄 from t_student
select max(age) from t_student 查询最大年龄
select max(age),min(age) from t_student
select max(age) as 最大年龄,min(age) as 最小年龄,avg(age) as 平均年龄 from t_student
select max(age) as 最大年龄,min(age) as 最小年龄,avg(age) as 平均年龄,count(*) as 总行数 from t_student
select * from t_student where name like 'y%'
查询以y开头后面有若干个字符。。。
select * from t_student where name like '%a%'
查询含有a
select * from t_student order by age 按照年龄升序排列
select * from t_student order by age desc 按照年龄升序排列
select * from t_student where name like 'y%' order by age
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