MySQL 8.0

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create table t(
    a varchar(30) 
    charset latin1
    default 'abc'
    not null
    comment 'cool column bro'
);
-- checking what the column looks like...
-- observe the non-default charset/collation, default value, not null constraint
-- and column
select table_name, column_name, column_default, is_nullable, character_maximum_length, character_set_name, collation_name, column_comment
  from information_schema.columns where table_name = 't';


TABLE_NAME
COLUMN_NAME
COLUMN_DEFAULT
IS_NULLABLE
CHARACTER_MAXIMUM_LENGTH
CHARACTER_SET_NAME
COLLATION_NAME
COLUMN_COMMENT


t
a
616263
NO
30
latin1
latin1_swedish_ci
cool column bro


 -- let me innocently expand the varchar len 
alter table t modify a varchar(40);

Records: 0  Duplicates: 0  Warnings: 0


-- checking what the column looks like again...
-- OOPS!!!! I've wiped the character set, collation,
-- NOT NULL constraint default value, and comment!
select table_name, column_name, column_default, is_nullable, character_maximum_length, character_set_name, collation_name, column_comment
from information_schema.columns where table_name = 't'; 


TABLE_NAME
COLUMN_NAME
COLUMN_DEFAULT
IS_NULLABLE
CHARACTER_MAXIMUM_LENGTH
CHARACTER_SET_NAME
COLLATION_NAME
COLUMN_COMMENT


t
a
null
YES
40
utf8mb4
utf8mb4_0900_ai_ci