课程学习
创建数据表
create table
customer (
c_customer_sk
integer,
c_customer_id
char(5),
c_first_name
char(6),
c_last_name char(8)
);
向表中插入记录
insert into
customer values
(6885, 1, 'Joes',
'Hunter'),
(4321, 2,
'Lily','Carter'),
(9527, 3, 'James',
'Cook'),
(9500, 4, 'Lucy',
'Baker');
查看数据
select * from
customer;
select * from
customer limit 2;
select c_first_name
as c_name from customer;
更新数据
update customer set
c_customer_sk = c_customer_sk * 2 where c_customer_sk < 5000;
删除数据
delete from
customer where c_first_name = 'Lucy';
delete from
customer;
删除表
drop table if
exists customer;
课后作业
1.创建一个表products
create table
products (
product_id integer,
product_name
char(20),
category char(30)
);
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', 'electronics');
insert into
products values
(1601, 'lamaze',
'toys'),
(1700, 'wait
interface', 'Books'),
(1666, 'harry
potter', 'toys');
3.获取表中一条记录、三条记录和所有记录
select * from
products limit 1;
select * from
products limit 3;
select * from
products;
4.将满足product_id > 1600的记录的product_id更新为product_id – 1000，并查看products中所有记录是否更新成功
update products set
product_id = product_id - 1000 where product_id > 1600;
select * from
products;
5.删除category为toys的所有记录，并查看products中数据是否删除成功
delete from
products where category = 'toys';
select * from
products;
6.删除products中所有数据，并查看数据是否删除成功
delete from
products;
select * from
products;
7.删除表products
drop table if
exists products;
总结：相对于第一天，基本操作相同，稍微增加了一些条件判断的操作。
