Data type default values support some expressions

[zimulala]

Feature Request

Is your feature request related to a problem? Please describe:

Replace Oracle's functions with some of mysql's own expression functions.

Describe the feature you'd like:

Currently, only the following expressions are supported without additional extensions. That is, only REPLACE(UPPER(uuid())," - ", ") is supported, and other expressions of replace are not supported.

• Data type default values support UPPER(SUBSTRING_INDEX(user(),'@',1)) #50966
  • user -> UPPER(SUBSTRING_INDEX(user(),'@',1))
• Data type default values support REPLACE(UPPER(uuid()), '-', '') #50937
  • sys_guid() -> REPLACE(UPPER(uuid()), '-', '')
• Data type default values support DATE_FORMAT(NOW(),'%Y-%m...') #51031
  • to_char(sysdate, 'yyyymm') -> DATE_FORMAT(NOW(),'%Y-%m')
  • to_char(sysdate,'yyyymmdd') -> DATE_FORMAT(NOW(),'%Y-%m-%d')
  • to_char(sysdate,'yyyy-mm-dd-hh24.mi.ss') -> DATE_FORMAT(NOW(),'%Y-%m-%d %H.%i.%s')
  • to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') -> DATE_FORMAT(NOW(),'%Y-%m-%d %H:%i:%s')
  • to_char(rawtohex(sys_guid())) -> REPLACE(UPPER(uuid()), '-', '')
  • trunc(sysdate,'mm') -> DATE_FORMAT(NOW(),'%Y-%m-%d')
• Data type default values support STR_TO_DATE('1980-01-01','%Y-%m-%d') #51276
  • to_date('1980-01-01', 'yyyy-mm-dd') -> STR_TO_DATE('1980-01-01','%Y-%m-%d')
  • to_date('9999-01-01', 'yyyy-mm-dd') -> STR_TO_DATE('9999-01-01','%Y-%m-%d')

Add tests

• Add expression default values feature relevant tests for different data types and default keywords. #51481
• Move related(default value expression) tests in db_integration_test to tests/integrationtest/r/ddl #51503
• Add expression default values feature relevant tests for "modify column", "set/drop default" and "add index" #51570
• Add expression default values feature relevant tests for different types of tables and indexes #51686

Related issues

• The "extra" field in the result of "show columns" with default value expressions is not processed #51462
• When the default value is an expression, changing it to a constant by "set default" can be problematic #51554
• Table creation with auto_increment and default expressions behaves differently from MySQL #51587
• Make the error message of the default value expression more appropriate. #51703

Step 2

• Support alter table ... add column in adding expression default values feature  #52676

Related issues

• I don't think this is a bug, it's just inconsistent behavior with MySQL:
  • Different beheviors when performing add column in adding expression default values feature