openGauss每日一练第2天 | 学习心得体会

1.创建一个表products

create table products (product_id integer, product_name char(20), category char(30));
comment on column products.product_id is '产品编号';
comment on column products.product_name is '产品名';
comment on column products.category is '种类';

2.向表中插入数据，采用一次插入一条和多条记录的方式

一次插入一条数据
insert into products values(1502,'olympus camera','electrncs');
insert into products values(1601,'lamaze','toys');
insert into products values(1700,'wait interface','Books');
insert into products values(1666,'harry potter','toys');
--一次插入多条数据
insert into products values 
(1502,'olympus camera','electrncs')，
(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

--获取表中一条记录
select * from products limit 1;
--获取表中三条记录
select * from products limit 1;
--获取表中所有记录
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 count(*) from products;

7.删除表products

drop table products;