离谱！原来执行计划不仅会影响执行效率，还会影响执行结果集
BUG ？一个小小的UPDATE语句竟然还涉及这么多门路
- UPDATE FROM 细节探究
- 小结一下
看腻了就来听听视频演示吧（持续更新中）：https://www.bilibili.com/video/BV1DH4y1c7ni/
UPDATE FROM 细节探究
创建测试表和数据：
drop table IF EXISTS test1;
CREATE TABLE test1(id int,name text);
insert into test1 values(1,'PostgreSQL'),(2,'Oracle'),(3,'MySQL');
drop table IF EXISTS test2;
CREATE TABLE test2(id int,name text);
insert into test2 values(5,'TiDB'),(1,'PG'),(2,'OG'),(2,'OG-HA'),(2,'ABCDEFG'),(2,'A'),(2,'abcefg'),(2,'O'),(2,'SY'),(2,'DBA'),(2,'og'),(2,'openGauss'),(4,'Oracle'),(6,'SQLServer');
select * from test1 order by 1;
select ctid,* from test2 order by id,name;
select ctid,* from test2 order by id,ctid;
