兼容虚拟列语法
atlasdb=# CREATE TABLE gtest0 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (55) STORED);
NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "gtest0_pkey" for table "gtest0"
CREATE TABLE
atlasdb=# CREATE TABLE gtest1 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index "gtest1_pkey" for table "gtest1"
CREATE TABLE
atlasdb=# insert into gtest0(a ) values (111);
INSERT 0 1
atlasdb=# select * from gtest0;
a | b
-----+----
111 | 55
(1 row)
atlasdb=# insert into gtest1(a ) values (111);
INSERT 0 1
atlasdb=# select * from gtest1;
a | b
-----+-----
111 | 222
(1 row)
