sql data table and field comments

【Foreword】

      When designing the database, it is convenient for developers to query and identify, so sql allows to add comments    

 

【main body】

1. Write a comment when creating a table

create table test1(
    field_name int comment 'Comment of the field'
)comment='Comment of the table';

 

2. Modify the comments of the table

alter table test1 comment 'The comment of the modified table';

 

3. Modify the comment of the field

alter table test1 modify column field_name int comment 'Modified field comment';

--Note: just write the field name and field type as written

 

4. Ways to view table comments

-- look in the generated SQL statement

show create table test1;

-- look in the metadata table

use information_schema;
select * from TABLES where TABLE_SCHEMA='my_db' and TABLE_NAME='test1' \G 

 

5. How to view field annotations

--show

show full columns from test1;

-- look in the metadata table

select * from COLUMNS where TABLE_SCHEMA='my_db' and TABLE_NAME='test1' \G

 

 

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