1.order_by
select * from products order_by salary desc;(倒叙)
select * from products order_by salary asc;
2.利用正则表达式
select * from products where name regexp ‘.000‘;
select * from products where name regexp ‘[123] 000‘;
3.利用函数
select upper(name) from products ;
select * from products where Year(order_date) = 2020 and Month(order_date) = 5;
select avg(salary) from products;(平均值)
select count(*) from products;（计数）
select max(salary) as min_salary from products;（最大值）
select sum(salary) as sum_salary from products;（求和）