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mysql creates tables with explanations and adds comments to tables and fields:

1. Create a table with explanations

CREATE TABLE test_table( t_id INT(11) PRIMARY KEY AUTO_INCREMENT COMMENT 'SET PRIMARY KEY AUTO INCREMENT', t_name VARCHAR(64) COMMENT 'COLUMN COMMENT') COMMENT ='TABLE COMMENT ';

2. Modify table notes

ALTER TABLE test_table COMMENT 'modify table comment';

3. View table notes

SELECT TABLE_COMMENT FROM information_schema.TABLES WHERE TABLE_SCHEMA = 'test' AND TABLE_NAME = 'test_table'

4. Add columns with comments

alter table test_table add t_age int(11) comment 'AGE'

5. Modify column names with comments

ALTER TABLE test_table CHANGE t_age t_sex VARCHAR(4) COMMENT 'sex'

6. Modify column comments

ALTER TABLE test_table MODIFY COLUMN t_sex VARCHAR(30) NOT NULL COMMENT 'male female'

Note: When modifying, complete definition of the field should be written, such as field type, attribute, etc. Never modify a comment by overwriting other attributes defined by that field.

7. Delete columns

alter table test_table drop column t_sex

8. Query table field information

SHOW FULL COLUMNS FROM test_table

9. Delete table

--Single deletion drop table--Batch deletion drop table Table 1, Table 2, Table 3

10. Modify a field value in batches

UPDATE test_table SET t_name = REPLACE(t_name, 'test', 't')

As shown in the figure:

Example: Before running

Post Run:

The above is mysql for data tables and fields to add comments details, more please pay attention to other related articles!

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