自己安装的openGauss环境
启动openGauss
gs_ctl -D /gauss/data/db1/ start
登录openGauss
gsql -d postgres -p 26000 -r
1.创建表1并在表中插入数据，分别指定字段和整行为缺省值
create table products
(product_id INTEGER,
product_name Char(30)
);
insert into products(product_id,product_name) values(1,‘des’),(2,DEFAULT);
insert into products DEFAULT VALUES;
select * from products;
2.创建表2并将表1的数据全部导入表2中
create table new_products
(product_id INTEGER,
product_name Char(30)
);
insert into new_products select * from products;
select * from new_products;
3.创建表3和表4，并合并两个表的数据到表3
create table student
(
id integer,
name char(20),
age integer
);
insert into student(id,name,age) values(100101,‘张一’,8),(100105,‘李五’,7),(100107,‘黄七’,9);
create table new_student
(
id integer,
name char(20),
age integer
);
insert into new_student(id,name,age) values(100105,‘赵八’,8),(100108,‘陈八’,10),(100109,‘刘久’,9);
MERGE INTO new_student np
USING student p
ON (np.id = p.id )
WHEN MATCHED THEN
UPDATE SET np.name = p.name, np.age = p.age
WHEN NOT MATCHED THEN
INSERT VALUES (p.id, p.name, p.age);
select * from new_student;
4.将表3的数据输出到文件，再将文件中的数据导入到表5
copy new_student to ‘/home/omm/new_student.dat’;
CREATE TABLE new_student_add (LIKE new_student);
copy new_student_add from ‘/home/omm/new_student.dat’;
select * from new_student_add;
