MySql 建表、添加字段、修改字段、添加索引SQL语句写法及SQL索引

---------添加索引方法---------
1.添加PRIMARY KEY（主键索引）
mysql>ALTER TABLE `table_name` ADD PRIMARY KEY ( `column` )
2.添加UNIQUE(唯一索引)
mysql>ALTER TABLE `table_name` ADD UNIQUE (
`column`
)

3.添加INDEX(普通索引)
mysql>ALTER TABLE `table_name` ADD INDEX index_name ( `column` )

4.添加FULLTEXT(全文索引)
mysql>ALTER TABLE `table_name` ADD FULLTEXT (
`column`
)

5.添加多列索引
mysql>ALTER TABLE `table_name` ADD INDEX index_name ( `column1`, `column2`, `column3` )

https://www.cnblogs.com/bk7788/p/6050184.html

查看表的索引：
show index from table_name（表名）
https://blog.csdn.net/superdangbo/article/details/79283752

SQL Server索引

--删除索引
if exists(select name from sysindexes where name = 'suoyin')
drop index temp.suoyin ---如果存在这个名字的索引，则删除这个索引
create nonclustered index suoyin_name on temp(Name)

--主键，加聚集索引
ALTER TABLE [dbo].[FcyOrder] ADD  CONSTRAINT [PK_FcuencyOrder] PRIMARY KEY CLUSTERED (
    [FreqOrderId] ASC
)
go

CREATE NONCLUSTERED INDEX [IX_Code] ON [dbo].[Fct_Product] ([ProductCode]) ON [PRIMARY]
GO

CREATE INDEX [IX_OrderId] ON [dbo].[FncyOrder]
([OrderId] ASC)
GO

CREATE INDEX [IDX_Disabled_ChanyCodeAndName] ON [dbo].[Fcommodity]
([Disabled] ASC)
INCLUDE ([ChadityCode], [ChaodityName])
GO

CREATE UNIQUE INDEX [IDX_SiteWarehouseAndSerialNumber] ON [dbo].[FcquestInfo]
([SerialNumber] ASC, [SiouseId] ASC)
WITH (IGNORE_DUP_KEY = ON)
GO

CREATE UNIQUE INDEX [IX_tockFove_FoveNo] ON [dbo].[TockFove]
([FveNo] ASC)
WITH (IGNORE_DUP_KEY = ON)
GO