openGauss每日一练第2天 |对表的操作

作业：

1.创建一个表products

omm=# create table products ( product_id integer,product_name char(30),caregory char(20));

CREATE TABLE

2.向表中插入数据，采用一次插入一条和多条记录的方式

一条插入

omm=# insert into products values (1502,'olympus camera','electrncs');
INSERT 0 1

多条插入

omm=# insert into products values (1601,'lamaze','toys'),(1700,'wait interface','Books'),(1666,'harry potter','toys');
INSERT 0 3

3.获取表中一条记录、三条记录和所有记录

omm=# select * from products limit 1;
product_id | product_name | caregory
------------+--------------------------------+----------------------
1502 | olympus camera | electrncs
(1 row)

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

omm=# product_id | product_name | caregory
------------+--------------------------------+----------------------

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

omm=# update products set product_id = product_id - 1000 where product_id > 1600;
UPDATE 3

omm=# select * from products;
product_id | product_name | caregory
------------+--------------------------------+----------------------
1502 | olympus camera | electrncs
omm=# 1502 | olympus camera | electrncs
601 | lamaze | toys
700 | wait interface | Books
666 | harry potter | toys
(5 rows)

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

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

6.删除products中所有数据，并查看数据是否删除成功

omm=# delete from products;
DELETE 3
omm=# select * from products ;
product_id | product_name | caregory
------------+--------------+----------
(0 rows)

7.删除表products

omm=# drop table products ;
DROP TABLE