Mysql alter table structure: add, delete, Modify Field, adjust field order

Mysql changes the table structure: add, delete, modify, and adjust the field order to add a field: altertable 'user _ movement_log 'AddcolumnGatewayIdintnotnulldefault0AFTER 'regionid' (after which field is added) Delete the field: altertable 'user _ movement_log 'dropcolumnGatewayi

Mysql changes the table structure: add, delete, modify fields, adjust the field order to add fields: alter table 'user _ movement_log 'Add column GatewayId int not null default 0 AFTER 'regionid' (AFTER which field is added) delete field: alter table 'user _ movement_log' drop column Gatewayi

Mysql changes the table structure: adding, deleting, modifying, and adjusting the field order
Add field:

Alter table 'user _ movement_log'
Add column GatewayId int not null default 0 AFTER 'regionid' (AFTER which field is added)

Delete field:

Alter table 'user _ movement_log 'drop column Gatewayid

Adjust the field order:

Alter table 'user _ movement_log 'CHANGE 'gatewayid' int not null default 0 AFTER RegionID

// Primary key

Alter table tabelname add new_field_id int (5) unsigned default 0 not null auto_increment, add primary key (new_field_id );

// Add a new column

Alter table t2 add d timestamp;
Alter table infos add ex tinyint not null default '0 ';

// Delete a column

Alter table t2 drop column c;

// Rename a column

Alter table t1 change a B integer;

// Change the column type

Alter table t1 change B bigint not null;
Alter table infos change list tinyint not null default '0 ';

// Rename the table

Alter table t1 rename t2;

Add Index

Mysql> alter table tablename change depno int (5) not null;
Mysql> alter table tablename add index name (field name 1 [, field name 2…]);
Mysql> alter table tablename add index emp_name (name );

Index with primary keywords

Mysql> alter table tablename add primary key (id );

Add an index with unique conditions

Mysql> alter table tablename add unique emp_name2 (cardnumber );

Delete An index

Mysql> alter table tablename drop index emp_name;

Modify Table:

Add field:

Mysql> alter table table_name ADD field_name field_type;

Modify the original field name and type:

Mysql> alter table table_name CHANGE old_field_name new_field_name field_type;

Delete field:

Mysql> alter table table_name DROP field_name;