添加索引的幾種方法
1.添加PRIMARY KEY(主鍵索引):
ALTER TABLE table_name
ADD PRIMARY KEY ( column
)
‘table_name’ 表名
column 字段
將table_name表的column字段設置爲主鍵
2.添加UNIQUE(唯一索引) :
ALTER TABLE table_name
ADD UNIQUE ( column
)
3.添加INDEX(普通索引) :
寫法一:ALTER TABLE table_name
ADD INDEX index_name ( column
)
寫法二:CREATE INDEX index_name ON table_name
(column1
,column2
,column3
)
4.添加FULLTEXT(全文索引) :
ALTER TABLE table_name
ADD FULLTEXT ( column
)
5.添加多列索引(聯合索引):
寫法一:ALTER TABLE table_name
ADD INDEX index_name ( column1
, column2
, column3
)
寫法二:CREATE INDEX index_name ON table_name
(column1
,column2
,column3
)
6. 查詢表索引
SHOW INDEX FROM table_name
;
7. 刪除索引
DROP INDEX index_name ON table_name
;
最後附上索引詳解地址:https://www.cnblogs.com/sheseido/p/5825441.html
https://www.cnblogs.com/nickchen121/p/11155947.html