openGauss每日一练第1天 |SQL语句基本操作

心得：

课后作业：

切换用户、进入sql环境

root@modb:~#
root@modb:~# su - omm
omm@modb:~$ gsql -r
gsql ((openGauss 2.0.0 build 78689da9) compiled at 2021-03-31 21:03:52 commit 0 last mr )
Non-SSL connection (SSL connection is recommended when requiring high-security)
Type "help" for help.

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
omm=# 

2. 向表中插入数据，采用一次插入一条和多条记录的方式

omm=# insert into products (product_id,product_name,caregory) values (1502,'olympus camera','electrncs');
INSERT 0 1
omm=# 
omm=#  insert into products values (1601,'lamaze','toys'),(1700,'wait interface','Books'),(1666,'harry potter','toys');
INSERT 0 3

3. 查询表中所有记录及记录数

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

omm=# 

omm=# select count(*) from products;
 count 
-------
     4
(1 row)

omm=# 

4. 查询表中所有category记录，并将查询结果按升序排序

omm=# select caregory from products order by caregory;
       caregory       
----------------------
 Books               
 electrncs           
 toys                
 toys                
(4 rows)

omm=# 
5. 查询表中category为toys的记录
omm=# select * from products where caregory='toys';
 product_id |          product_name          |       caregory       
------------+--------------------------------+----------------------
       1601 | lamaze                         | toys                
       1666 | harry potter                   | toys                
(2 rows)

omm=# 

6. 删除表products

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