openGauss每日一练第 13 天 | 随堂笔记

学习openGauss表的创建、搜索路径和访问方法等

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 reason_tb1
(
r_reason_sk integer,
r_reason_id character(16),
r_reason_desc character(100)
);
insert into reason_tb1 values(1, 'AAAAAAAABAAAAAAA', 'reason1');
–没有数值的字段将被填充为字段的缺省值

insert into reason_tb1 values(1, 'AAAAAAAABAAAAAAA');
–明确字段为缺省值

insert into reason_tb1 values(1, 'AAAAAAAABAAAAAAA', DEFAULT);
–明确整行为缺省值

insert into reason_tb1 DEFAULT VALUES;
select * from reason_t1;

2.创建表2并将表1的数据全部导入表2中

CREATE TABLE reason_tb2
(
r_reason_sk integer,
r_reason_id character(16),
r_reason_desc character(100)
);
–将查询结果作为插入的数据

INSERT INTO reason_t2 SELECT * FROM reason_t1;
select * from reason_t2;

3.创建表3和表4，并合并两个表的数据到表3

CREATE TABLE newproducts1
( product_id INTEGER,
product_name VARCHAR2(60),
category VARCHAR2(60)
);
CREATE TABLE newproducts12
( product_id INTEGER,
product_name VARCHAR2(60),
category VARCHAR2(60)
);
–将表数据输出到stdout

copy reason_t1 to stdout;
–将表数据拷贝到文件

copy reason_tb1 to '/home/omm/reason1.dat';
CREATE TABLE reason_t3 (LIKE reason_t1);

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 reason_t5 from '/home/omm/reason5.dat';
select * from reason_t4;