带IF NOT EXISTS 关键字作用表示表不存在时才创建。

teledb=# create table t(id int,mc text);
CREATE TABLE
teledb=#  create table t(id int,mc text);
ERROR:  relation "t" already exists
teledb=#  create table IF NOT EXISTS t(id int,mc text);
NOTICE:  relation "t" already exists, skipping
CREATE TABLE