Modify SQL database table fields (except CRUD) (index)

1: New Table

CREATE TABLE `表名` (
  `字段1` bigint(20) NOT NULL,
  `字段2` varchar(48) DEFAULT NULL,
  `字段3` int(24) DEFAULT NULL,
  `字段4` varchar(48) DEFAULT NULL,
  `字段5` varchar(48) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

2: Increase the field

ALTER TABLE 表名 ADD COLUMN 字段 VARCHAR(2) 
DEFAULT NULL;

Note: mysql will automatically look for automatic semicolon terminator

3: Remove fields

ALTER TABLE 表名 DROP 字段;

4: Modify the field

ALTER TABLE 表名 MODIFY COLUMN 字段 VARCHAR(4) 
DEFAULT NULL;

5: Field to add an index ALTER

PRIMARY KEY primary key index: MySQL> the ALTER TABLE table_namethe ADD PRIMARY KEY ( column)
UNIQUE unique index: MySQL> the ALTER TABLE table_namethe ADD UNIQUE ( column)
INDEX general index: MySQL> the ALTER TABLE table_namethe ADD INDEX index_name ( column)
FULLTEXT full-text index: MySQL> the ALTER TABLE table_namethe ADD FULLTEXT ( column)
iNDEX multi-column indexes: MySQL> the ALTER TABLE table_namethe ADD iNDEX index_name ( column1, column2, column3)
index_name may be empty, empty columns MySQL will assign a name based on the first index. Field quotes

6: Field to add an index create

index index_name ON table_name Create (the column_list);
Create UNIQUE index index_name ON table_name (the column_list);　
index_name not empty, field without quotes

7: Field remove the index ALTER

alter table table_name drop index index_name ;

7: Field to add an index ALTER

drop index index_name on table_name ;