Description of the actual operation syntax for modifying a MySQL table

The following articles mainly describe MySQL table modification, that is, adding or deleting columns and creating or canceling indexes. We all know that after MySQL creates a related database, if a table is created and some fields are added, how can I add fields in the future?

A: Use alter table )!

Alter table Syntax:

 
 

  
  
ALTER [IGNORE] TABLE tbl_name  
  
  
alter_specification [, alter_specification] ...  
  
  
alter_specification:  
  
  
ADD [COLUMN] column_definition [FIRST | AFTER col_name ]  
  
  
| ADD [COLUMN] (column_definition,...)  
  
  
| ADD INDEX [index_name] [index_type] (index_col_name,...)  
  
  
| ADD [CONSTRAINT [symbol]]  
  
  
PRIMARY KEY [index_type] (index_col_name,...)  
  
  
| ADD [CONSTRAINT [symbol]]  
  
  
UNIQUE [index_name] [index_type] (index_col_name,...)  
  
  
| ADD [FULLTEXT|SPATIAL] [index_name] (index_col_name,...)  
  
  
| ADD [CONSTRAINT [symbol]]  
  
  
FOREIGN KEY [index_name] (index_col_name,...)  
  
  
[reference_definition]  
  
  
| ALTER [COLUMN] col_name {SET DEFAULT literal | DROP DEFAULT}  
  
  
| CHANGE [COLUMN] old_col_name column_definition  
  
  
[FIRST|AFTER col_name]  
  
  
| MODIFY [COLUMN] column_definition [FIRST | AFTER col_name]  
  
  
| DROP [COLUMN] col_name  
  
  
| DROP PRIMARY KEY  
  
  
| DROP INDEX index_name  
  
  
| DROP FOREIGN KEY fk_symbol  
  
  
| DISABLE KEYS  
  
  
| ENABLE KEYS  
  
  
| RENAME [TO] new_tbl_name  
  
  
| ORDER BY col_name  
  
  
| CONVERT TO CHARACTER SET charset_name [COLLATE collation_name]  
  
  
| [DEFAULT] CHARACTER SET charset_name [COLLATE collation_name]  
  
  
| DISCARD TABLESPACE | IMPORT TABLESPACE | table_options  
  
  
| partition_options  
  
  
| ADD PARTITION partition_definition  
  
  
| DROP PARTITION partition_names  
  
  
| COALESCE PARTITION number  
  
  
| REORGANIZE PARTITION partition_names INTO (partition_definitions)  
  
  
| ANALYZE PARTITION partition_names  
  
  
| CHECK PARTITION partition_names  
  
  
| OPTIMIZE PARTITION partition_names  
  
  
| REBUILD PARTITION partition_names  
  
  
| REPAIR PARTITION pa   
 
 

The above content is an introduction to MySQL table modification. I hope you will have some gains.