今天学习openGauss，基本练习，以下是作业和心得
1.连接openGauss
Welcome to 墨天轮.
This is Web Terminal of modb.pro; Good Good Study, Day Day Up.
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.
2.创建表
omm=# CREATE TABLE customer_t
omm-# ( c_customer_sk integer,
omm(# c_customer_id char(5),
omm(# c_first_name char(6),
omm(# c_last_name char(8)
omm(# ) ;
omm=# CREATE TABLE
创建表成功！
3.插入数据
单条数据插入
omm=# INSERT INTO customer_t (c_customer_sk, c_customer_id, c_first_name,c_last_name) VALUES (3769, 5, 'Grace','White');
INSERT 0 1
omm=# INSERT INTO customer_t VALUES (3769, 5, 'Grace','White');
INSERT 0 1
多条数据批量插入
omm=# INSERT INTO customer_t (c_customer_sk, c_customer_id, c_first_name,c_last_name) VALUES
omm-# (6885, 1, 'Joes', 'Hunter'),
omm-# (4321, 2, 'Lily','Carter'),
omm-# (9527, 3, 'James', 'Cook'),
omm-# (9500, 4, 'Lucy', 'Baker');
INSERT 0 4
4.查看表记录数
omm=# select count(*) from customer_t;
count
-------
6
(1 row)
5.查看表记录
omm=# select * from customer_t;
c_customer_sk | c_customer_id | c_first_name | c_last_name
---------------+---------------+--------------+-------------
3769 | 5 | Grace | White
3769 | 5 | Grace | White
6885 | 1 | Joes | Hunter
4321 | 2 | Lily | Carter
9527 | 3 | James | Cook
9500 | 4 | Lucy | Baker
(6 rows)
6.查看表单列数据
omm=# select c_first_name from customer_t;
c_first_name
--------------
Grace
Grace
Joes
Lily
James
Lucy
(6 rows)
7.去重查询
omm=# SELECT DISTINCT(c_first_name) from customer_t;
c_first_name
--------------
James
Grace
Lucy
Joes
Lily
(5 rows)
8.查看表并按c_customer_id升级排序
omm=# select * from customer_t order by c_customer_id;
c_customer_sk | c_customer_id | c_first_name | c_last_name
---------------+---------------+--------------+-------------
6885 | 1 | Joes | Hunter
4321 | 2 | Lily | Carter
9527 | 3 | James | Cook
9500 | 4 | Lucy | Baker
3769 | 5 | Grace | White
3769 | 5 | Grace | White
(6 rows)
9.查看表customer_t中c_first_name为Lily的记录
omm=# select * from customer_t where c_first_name = 'Lily';
c_customer_sk | c_customer_id | c_first_name | c_last_name
---------------+---------------+--------------+-------------
4321 | 2 | Lily | Carter
(1 row)
10.删除表
omm=# drop table customer_t;
DROP TABLE
11.作业
omm=# create table products(product_id integer,product_name char(30),category char(20));
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=# select * from products;
product_id | product_name | category
------------+--------------------------------+----------------------
1502 | olympus camera | electrncs
omm=# 1601 | lamaze | toys
1700 | wait interface | Books
1666 | harry potter | toys
(4 rows)
omm=# select count(*) from products;
count
-------
4
(1 row)
omm=# select category from products order by category;
category
----------------------
Books
electrncs
toys
toys
(4 rows)
omm=# select * from products where category='toys';
product_id | product_name | category
------------+--------------------------------+----------------------
1601 | lamaze | toys
1666 | harry potter | toys
(2 rows)
omm=# drop table products;
DROP TABLE
Have a nice day!
