openGauss每日一练第2天

学习目标

学习openGauss数据库查询、更新和删除基本使用。

课程学习

连接openGauss 

su - omm

gsql -r

1.创建一个表products

2.向表中插入数据，采用一次插入一条和多条记录的方式

3.获取表中一条记录、三条记录和所有记录

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

5.删除category为toys的所有记录，并查看products中数据是否删除成功

6.删除products中所有数据，并查看数据是否删除成功

7.删除表products

omm=#
omm=# create table products(product_id integer,product_name char(30),category char(30));
CREATE TABLE
omm=# insert into products values(1502,'olympus camera','electrncs');
INSERT 0 1
omm=# insert into products values(1601,'lamaze','toys'),(1700,'wait interface','Books'),(1666,'harry potter','toys');
INSERT 0 3
omm=#
omm=#
omm=#
omm=#
omm=#
omm=#
omm=# select * from products limit 1;
product_id | product_name | category
------------+--------------------------------+--------------------------------
1502 | olympus camera | electrncs
(1 row)

omm=# select * from products limit 2;
product_id | product_name | category
------------+--------------------------------+--------------------------------
1502 | olympus camera | electrncs
1601 | lamaze | toys
(2 rows)

omm=# select * from products limit 3;
product_id | product_name | category
------------+--------------------------------+--------------------------------
1502 | olympus camera | electrncs
1601 | lamaze | toys
1700 | wait interface | Books
(3 rows)

omm=# select * from products;
product_id | product_name | category
------------+--------------------------------+--------------------------------
1502 | olympus camera | electrncs
1601 | lamaze | toys
1700 | wait interface | Books
1666 | harry potter | toys
(4 rows)

omm=#

omm-#
omm-#

omm=# update products set product_id=product_id-1000 where product_id>1600;
UPDATE 3
omm=# select * from products;
601 | lamaze | toys
700 | wait interface | Books
666 | harry potter | toys
(4 rows)

omm=# product_id | product_name | category
------------+--------------------------------+--------------------------------
1502 | olympus camera | electrncs
omm=#

omm=#
omm=# delete from products where category='toys';
DELETE 2
omm=# select * from products;
product_id | product_name | category
------------+--------------------------------+--------------------------------
1502 | olympus camera | electrncs
700 | wait interface | Books
(2 rows)

omm=# delete products;
DELETE 2
omm=# select * from products;
product_id | product_name | category
------------+--------------+----------
(0 rows)

omm=# drop table products;
DROP TABLE
omm=# 

总结：通过本次学习掌握了opengauss数据库表的条件查询和修改。