1.添加PRIMARY KEY(主鍵索引)mysql
語法:ALTER TABLE `表名` ADD PRIMARY KEY ( `列名稱` )sql
mysql>ALTER TABLE `table_name` ADD PRIMARY KEY ( `column` )spa
2.添加UNIQUE(惟一索引) 索引
語法:ALTER TABLE `表名` ADD UNIQUE ( `列名稱`)ci
mysql>ALTER TABLE `table_name` ADD UNIQUE ( `column`) table
3.添加INDEX(普通索引) 語法
語法:ALTER TABLE `表名` ADD INDEX index_name ( `列名稱` )tab
mysql>ALTER TABLE `table_name` ADD INDEX index_name ( `column` ) co
4.添加FULLTEXT(全文索引) index
語法:ALTER TABLE `表名` ADD FULLTEXT ( `列名稱`)
mysql>ALTER TABLE `table_name` ADD FULLTEXT ( `column`)
5.添加多列索引
語法:ALTER TABLE `表名` ADD INDEX index_name ( `列名稱`, `列名稱`, `列名稱` )
mysql>ALTER TABLE `table_name` ADD INDEX index_name ( `column1`, `column2`, `column3` )
想要查看錶有幾個字段設置了索引
語法;SHOW INDEX FROM `表名`
mysql>SHOW INDEX FROM `cccinfo`