The Book

ALTER [IGNORE] TABLE tbl_name action[, action …]

In this code, action refers to an action as defined below. ALTER TABLE queries may be used to change the definition of a table without losing any of the information in that table (except in obvious cases, such as the deletion of a column). Here are the main actions that are possible:

ADD [COLUMN] create_definition [FIRST | AFTER column_name]

ADD INDEX [index_name] (index_col_name, …)

ADD FULLTEXT [index_name] (index_col_name, …)

ADD PRIMARY KEY (index_col_name, …)

ADD UNIQUE [index_name] (index_col_name, …)

ALTER [COLUMN] col_name {SET DEFAULT value | DROP DEFAULT}

CHANGE [COLUMN] col_name create_definition

DISABLE KEYS / ENABLE KEYS

DROP [COLUMN] col_name

DROP PRIMARY KEY / DROP INDEX index_name

MODIFY [COLUMN] create_definition

ORDER BY col_name

RENAME [TO] new_tbl_name

table_options

ANALYZE TABLE tbl_name[, tbl_name, …]