MySQL ALTERÓï·¨

 
ALTER [IGNORE] TABLE tbl_name alter_spec [, alter_spec ...]
alter_specification:
ADD [COLUMN] create_definition [FIRST | AFTER column_name ]
or ADD INDEX [index_name] (index_col_name,...)
or ADD PRIMARY KEY (index_col_name,...)
or ADD UNIQUE [index_name] (index_col_name,...)
or ALTER [COLUMN] col_name {SET DEFAULT literal | DROP DEFAULT}
or CHANGE [COLUMN] old_col_name create_definition
or MODIFY [COLUMN] create_definition
or DROP [COLUMN] col_name
or DROP PRIMARY KEY
or DROP INDEX index_name
or RENAME [AS] new_tbl_name
or table_options
eg:
mysql> alter table topics change hotico hot_count int(4);
mysql> alter table topics alter hot_count set default 1;
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mysql> alter table ±íÃû add index Ë÷ÒýÃû (×Ö¶ÎÃû1[£¬×Ö¶ÎÃû2 …]);
Àý×Ó£º mysql> alter table employee add index emp_name (name);
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mysql> alter table ±íÃû add primary key (×Ö¶ÎÃû);
Àý×Ó£º mysql> alter table employee add primary key(id);
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mysql> alter table ±íÃû add unique Ë÷ÒýÃû (×Ö¶ÎÃû);
Àý×Ó£º mysql> alter table employee add unique emp_name2(cardnumber);
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mysql> show index from ±íÃû;
Àý×Ó£º mysql> show index from employee;
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mysql> alter table ±íÃû drop index Ë÷ÒýÃû;
Àý×Ó£º mysql>alter table employee drop index emp_name;
ÐÞ¸Ä±í£ºÔö¼Ó×ֶΣºmysql> ALTER TABLE table_name ADD field_name field_type;
²é¿´±í£ºmysql> SELECT * from table_name;
ÐÞ¸ÄÔ­×Ö¶ÎÃû³Æ¼°ÀàÐÍ£ºmysql> ALTER TABLE table_name CHANGE old_field_name new_field_name field_type;
ɾ³ý×ֶΣºALTER TABLE table_name DROP field_name;