课后作业

1.创建一个表products

create table products(product_id  integer,product_name  Char(30),category   Char(20));

2.向表中插入数据，采用一次插入一条和多条记录的方式

insert into products values (1502,'olympus camera','electrncs');

insert into products values (1601,'lamaze','toys'),(1700,'wait interface','Books'),(1666,'harry potter','toys');

3.查询表中所有记录及记录数

select count(*) from products;

select * from products;

4.查询表中所有category记录，并将查询结果按升序排序

select category from products order by category ;

5.查询表中category为toys的记录

select * from products where category ='toys';

6.删除表products

drop table products ;