这一课学习openGauss导入数据，以下是课后作业打卡

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 t_ddzj_01(id int,name char(20),def_value char(60));
\d+ t_ddzj_01
insert into t_ddzj_01 values(1,'beijing','test');
insert into t_ddzj_01 values(2,'shanghai',default);
insert into t_ddzj_01 default values;
select * from t_ddzj_01;

2.创建表2并将表1的数据全部导入表2中

create table t_ddzj_02 as select * from t_ddzj_01;
select * from t_ddzj_02;

3.创建表3和表4，并合并两个表的数据到表3

create table t_ddzj_03(id int,name char(20),def_value char(60));
insert into t_ddzj_03 values (1,'name01','test1'),(2,'name02','test2'),(3,'name03','test3');
create table t_ddzj_04(id int,name char(20),def_value char(60));
insert into t_ddzj_04 values (1,'name04','test4'),(3,'name05','test5'),(4,'name06','test6');
select * from t_ddzj_03;
select * from t_ddzj_04;

merge into t_ddzj_03 t3
using t_ddzj_04 t4
on (t4.id = t3.id) 
when matched then 
update set t3.name = t4.name,t3.def_value = t4.def_value 
when not matched then
insert values(t4.id,t4.name,t4.def_value);

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 t_ddzj_03 to '/home/omm/t_ddzj_03.dat';
create table t_ddzj_05(id int,name char(20),def_value char(60));
copy t_ddzj_05 from '/home/omm/t_ddzj_03.dat';
select * from t_ddzj_05;