ALTER TABLE Statement | WITH PARSER  parser_name | COMMENT ’ string ’ | {VISIBLE | INVISIBLE} } table_options : table_option  [[,]  table_option ] ... table_option : { AUTOEXTEND_SIZE [=]  value | AUTO_INCREMENT [=]  value | AVG_ROW_LENGTH [=]  value | [DEFAULT] CHARACTER SET [=]  charset_name | CHECKSUM [=] {0 | 1} | [DEFAULT] COLLATE [=]  collation_name | COMMENT [=] ’ string ’ | COMPRESSION [=] {’ZLIB’ | ’LZ4’ | ’NONE’} | CONNECTION [=] ’ connect_string ’ | {DATA | INDEX} DIRECTORY [=] ’ absolute path to directory ’ | DELAY_KEY_WRITE [=] {0 | 1} | ENCRYPTION [=] {’Y’ | ’N’} | ENGINE [=]  engine_name | ENGINE_ATTRIBUTE [=] ’ string ’ | INSERT_METHOD [=] { NO | FIRST | LAST } | KEY_BLOCK_SIZE [=]  value | MAX_ROWS [=]  value | MIN_ROWS [=]  value | PACK_KEYS [=] {0 | 1 | DEFAULT} | PASSWORD [=] ’ string ’ | ROW_FORMAT [=] {DEFAULT | DYNAMIC | FIXED | COMPRESSED | REDUNDANT | COMPACT} | SECONDARY_ENGINE_ATTRIBUTE [=] ’ string ’ | STATS_AUTO_RECALC [=] {DEFAULT | 0 | 1} | STATS_PERSISTENT [=] {DEFAULT | 0 | 1} | STATS_SAMPLE_PAGES [=]  value | TABLESPACE  tablespace_name  [STORAGE {DISK | MEMORY}] | UNION [=] ( tbl_name [, tbl_name ]...) } partition_options : (see CREATE TABLE options) ALTER TABLE  changes the structure of a table. For example, you can add or delete columns, create or destroy indexes, change the type of existing columns, or rename columns or the table itself. You can also change characteristics such as the storage engine used for the table or the table comment. •To use  ALTER TABLE , you need  ALTER ,  CREATE , and  INSERT  privileges for the table. Renaming a table requires  ALTER  and  DROP  on the old table,  ALTER ,  CREATE , and  INSERT  on the new table. •Following the table name, specify the alterations to be made. If none are given,  ALTER TABLE  does nothing. •The syntax for many of the permissible alterations is similar to clauses of the  CREATE TABLE  statement. column_definition  clauses use the same syntax for  ADD  and  CHANGE  as for  CREATE TABLE . For more information, see Section 13.1.20, “CREATE TABLE Statement” . •The word  COLUMN  is optional and can be omitted, except for  RENAME COLUMN  (to distinguish a column- renaming operation from the  RENAME  table-renaming operation). •Multiple  ADD ,  ALTER ,  DROP , and  CHANGE  clauses are permitted in a single  ALTER TABLE  statement, separated by commas. This is a MySQL extension to standard SQL, which permits only one of each clause per  ALTER TABLE  statement. For example, to drop multiple columns in a single statement, do this: ALTER TABLE t2 DROP COLUMN c, DROP COLUMN d; 2483