create schema infomation_schema_test;
set current_schema = infomation_schema_test;
CREATE TABLE employees (emp_id INT, emp_name VARCHAR(50) NOT NULL) COMMENT='公司员工基本信息表';
CREATE TABLE employees2 (emp_id INT, emp_name VARCHAR(50) NOT NULL) COMMENT='Basic Information Form of Company Employees';
CREATE TABLE employees3 (emp_id INT primary key  AUTO_INCREMENT, emp_name VARCHAR(50) NOT NULL COMMENT 'this is a comment1');
NOTICE:  CREATE TABLE will create implicit sequence "employees3_emp_id_seq" for serial column "employees3.emp_id"
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "employees3_pkey" for table "employees3"
CREATE TABLE employees4 (emp_id INT primary key  AUTO_INCREMENT COMMENT 'this is a comment2', emp_time TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP);
NOTICE:  CREATE TABLE will create implicit sequence "employees4_emp_id_seq" for serial column "employees4.emp_id"
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "employees4_pkey" for table "employees4"
select * from information_schema.tables where table_schema = 'infomation_schema_test' and table_name = 'employees';
--?.*
--?.*
--?.*
(1 row)

select * from information_schema.tables where table_schema = 'infomation_schema_test' and table_name = 'employees2';
--?.*
--?.*
--?.*
(1 row)

select * from information_schema.columns where table_schema = 'infomation_schema_test' and table_name = 'employees3' and column_name = 'emp_id';
   table_catalog    |      table_schema      | table_name | column_name | ordinal_position | column_default | is_nullable | data_type | character_maximum_length | character_octet_length | numeric_precision | numeric_precision_radix | numeric_scale | datetime_precision | interval_type | interval_precision | character_set_catalog | character_set_schema | character_set_name | collation_catalog | collation_schema | collation_name | domain_catalog | domain_schema | domain_name |    udt_catalog     | udt_schema | udt_name | scope_catalog | scope_schema | scope_name | maximum_cardinality | dtd_identifier | is_self_referencing | is_identity | identity_generation | identity_start | identity_increment | identity_maximum | identity_minimum | identity_cycle | is_generated | generation_expression | is_updatable | column_type | column_comment |     extra      |           privileges            | column_key | srs_id 
--------------------+------------------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+--------------------+-----------------------+----------------------+--------------------+-------------------+------------------+----------------+----------------+---------------+-------------+--------------------+------------+----------+---------------+--------------+------------+---------------------+----------------+---------------------+-------------+---------------------+----------------+--------------------+------------------+------------------+----------------+--------------+-----------------------+--------------+-------------+----------------+----------------+---------------------------------+------------+--------
 contrib_regression | infomation_schema_test | employees3 | emp_id      |                1 | AUTO_INCREMENT | NO          | integer   |                          |                        |                32 |                       2 |             0 |                    |               |                    |                       |                      |                    |                   |                  |                |                |               |             | contrib_regression | pg_catalog | int4     |               |              |            |                     | 1              | NO                  | NO          |                     |                |                    |                  |                  |                | NEVER        |                       | YES          | integer     |                | AUTO_INCREMENT | select,insert,update,references | PRI        |       
(1 row)

select * from information_schema.columns where table_schema = 'infomation_schema_test' and table_name = 'employees4' and column_name = 'emp_id';
   table_catalog    |      table_schema      | table_name | column_name | ordinal_position | column_default | is_nullable | data_type | character_maximum_length | character_octet_length | numeric_precision | numeric_precision_radix | numeric_scale | datetime_precision | interval_type | interval_precision | character_set_catalog | character_set_schema | character_set_name | collation_catalog | collation_schema | collation_name | domain_catalog | domain_schema | domain_name |    udt_catalog     | udt_schema | udt_name | scope_catalog | scope_schema | scope_name | maximum_cardinality | dtd_identifier | is_self_referencing | is_identity | identity_generation | identity_start | identity_increment | identity_maximum | identity_minimum | identity_cycle | is_generated | generation_expression | is_updatable | column_type |   column_comment   |     extra      |           privileges            | column_key | srs_id 
--------------------+------------------------+------------+-------------+------------------+----------------+-------------+-----------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+--------------------+-----------------------+----------------------+--------------------+-------------------+------------------+----------------+----------------+---------------+-------------+--------------------+------------+----------+---------------+--------------+------------+---------------------+----------------+---------------------+-------------+---------------------+----------------+--------------------+------------------+------------------+----------------+--------------+-----------------------+--------------+-------------+--------------------+----------------+---------------------------------+------------+--------
 contrib_regression | infomation_schema_test | employees4 | emp_id      |                1 | AUTO_INCREMENT | NO          | integer   |                          |                        |                32 |                       2 |             0 |                    |               |                    |                       |                      |                    |                   |                  |                |                |               |             | contrib_regression | pg_catalog | int4     |               |              |            |                     | 1              | NO                  | NO          |                     |                |                    |                  |                  |                | NEVER        |                       | YES          | integer     | this is a comment2 | AUTO_INCREMENT | select,insert,update,references | PRI        |       
(1 row)

select * from information_schema.columns where table_schema = 'infomation_schema_test' and table_name = 'employees3' and column_name = 'emp_name';
   table_catalog    |      table_schema      | table_name | column_name | ordinal_position | column_default | is_nullable |     data_type     | character_maximum_length | character_octet_length | numeric_precision | numeric_precision_radix | numeric_scale | datetime_precision | interval_type | interval_precision | character_set_catalog | character_set_schema | character_set_name | collation_catalog  | collation_schema |   collation_name   | domain_catalog | domain_schema | domain_name |    udt_catalog     | udt_schema | udt_name | scope_catalog | scope_schema | scope_name | maximum_cardinality | dtd_identifier | is_self_referencing | is_identity | identity_generation | identity_start | identity_increment | identity_maximum | identity_minimum | identity_cycle | is_generated | generation_expression | is_updatable |    column_type    |   column_comment   | extra |           privileges            | column_key | srs_id 
--------------------+------------------------+------------+-------------+------------------+----------------+-------------+-------------------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+--------------------+-----------------------+----------------------+--------------------+--------------------+------------------+--------------------+----------------+---------------+-------------+--------------------+------------+----------+---------------+--------------+------------+---------------------+----------------+---------------------+-------------+---------------------+----------------+--------------------+------------------+------------------+----------------+--------------+-----------------------+--------------+-------------------+--------------------+-------+---------------------------------+------------+--------
 contrib_regression | infomation_schema_test | employees3 | emp_name    |                2 |                | NO          | character varying |                       50 |                    200 |                   |                         |               |                    |               |                    |                       |                      |                    | contrib_regression | pg_catalog       | utf8mb4_general_ci |                |               |             | contrib_regression | pg_catalog | varchar  |               |              |            |                     | 2              | NO                  | NO          |                     |                |                    |                  |                  |                | NEVER        |                       | YES          | character varying | this is a comment1 |       | select,insert,update,references |            |       
(1 row)

select * from information_schema.columns where table_schema = 'infomation_schema_test' and table_name = 'employees4' and column_name = 'emp_time';
   table_catalog    |      table_schema      | table_name | column_name | ordinal_position |          column_default           | is_nullable |        data_type         | character_maximum_length | character_octet_length | numeric_precision | numeric_precision_radix | numeric_scale | datetime_precision | interval_type | interval_precision | character_set_catalog | character_set_schema | character_set_name | collation_catalog | collation_schema | collation_name | domain_catalog | domain_schema | domain_name |    udt_catalog     | udt_schema |  udt_name   | scope_catalog | scope_schema | scope_name | maximum_cardinality | dtd_identifier | is_self_referencing | is_identity | identity_generation | identity_start | identity_increment | identity_maximum | identity_minimum | identity_cycle | is_generated | generation_expression | is_updatable |       column_type        | column_comment |                              extra                              |           privileges            | column_key | srs_id 
--------------------+------------------------+------------+-------------+------------------+-----------------------------------+-------------+--------------------------+--------------------------+------------------------+-------------------+-------------------------+---------------+--------------------+---------------+--------------------+-----------------------+----------------------+--------------------+-------------------+------------------+----------------+----------------+---------------+-------------+--------------------+------------+-------------+---------------+--------------+------------+---------------------+----------------+---------------------+-------------+---------------------+----------------+--------------------+------------------+------------------+----------------+--------------+-----------------------+--------------+--------------------------+----------------+-----------------------------------------------------------------+---------------------------------+------------+--------
 contrib_regression | infomation_schema_test | employees4 | emp_time    |                2 | b_db_statement_start_timestamp(0) | YES         | timestamp with time zone |                          |                        |                   |                         |               |                  0 |               |                    |                       |                      |                    |                   |                  |                |                |               |             | contrib_regression | pg_catalog | timestamptz |               |              |            |                     | 2              | NO                  | NO          |                     |                |                    |                  |                  |                | NEVER        |                       | YES          | timestamp with time zone |                | DEFAULT_GENERATED on update 'b_db_statement_start_timestamp(0)' | select,insert,update,references |            |       
(1 row)

drop table employees;
drop table employees2;
drop table employees3;
drop table employees4;
select * from information_schema.engines;
       engine       | support |                            comment                             | transactions | xa  | savepoints 
--------------------+---------+----------------------------------------------------------------+--------------+-----+------------
 MEMORY             | YES     | Hash based, stored in memory, useful for temporary tables      | NO           | NO  | NO
 InnoDB             | DEFAULT | Supports transactions, row-level locking, and foreign keys     | YES          | YES | YES
 PERFORMANCE_SCHEMA | YES     | Performance Schema                                             | NO           | NO  | NO
 MyISAM             | YES     | MyISAM storage engine                                          | NO           | NO  | NO
 ndbinfo            | NO      | MySQL Cluster system information storage engine                |              |     | 
 MRG_MYISAM         | YES     | Collection of identical MyISAM tables                          | NO           | NO  | NO
 BLACKHOLE          | YES     | /dev/null storage engine (anything you write to it disappears) | NO           | NO  | NO
 CSV                | YES     | CSV storage engine                                             | NO           | NO  | NO
 ARCHIVE            | YES     | Archive storage engine                                         | NO           | NO  | NO
 ndbcluster         | NO      | Clustered, fault-tolerant tables                               |              |     | 
(10 rows)

reset current_schema;
drop schema infomation_schema_test;