各位用户为了找寻关于Mysql主键相关的sql语句集锦的资料费劲了很多周折。这里教程网为您整理了关于Mysql主键相关的sql语句集锦的相关资料，仅供查阅，以下为您介绍关于Mysql主键相关的sql语句集锦的详细内容
添加表字段
alter table table1 add transactor varchar(10) not Null;
alter table table1 add id int unsigned not Null auto_increment primary key
修改某个表的字段类型及指定为空或非空
alter table 表名称 change 字段名称 字段名称 字段类型 [是否允许非空];
alter table 表名称 modify 字段名称 字段类型 [是否允许非空];
alter table 表名称 modify 字段名称 字段类型 [是否允许非空];
修改某个表的字段名称及指定为空或非空
alter table 表名称 change 字段原名称 字段新名称 字段类型 [是否允许非空
删除某一字段
ALTER TABLE mytable DROP 字段 名;
添加唯一键
ALTER TABLE `test2` ADD UNIQUE ( `userid`)
修改主键
ALTER TABLE `test2` DROP PRIMARY KEY ,ADD PRIMARY KEY ( `id` )
增加索引
ALTER TABLE `test2` ADD INDEX ( `id` )
ALTER TABLE `category ` MODIFY COLUMN `id` int(11) NOT NULL AUTO_INCREMENT FIRST ,ADD PRIMARY KEY (`id`);
修改主键的sql语句块如下:
22 declare @defname varchar(100) declare @cmd varchar(500) declare @tablename varchar(100) declare @keyname varchar(100) Set @tablename='Temp1' Set @keyname='id' --需要設置的key,分隔 select @defname= name FROM sysobjects so JOIN sysconstraints sc ON so.id = sc.constid WHERE object_name(so.parent_obj) = @tablename and xtype='PK' if @defname is not null begin select @cmd='alter table '+ @tablename+ ' drop constraint '+ @defname --print @cmd exec (@cmd) end else set @defname='PK_'+@keyname select @cmd='alter table '+ @tablename+ ' ADD constraint '+ @defname +' PRIMARY KEY CLUSTERED('+@keyname+')' exec (@cmd)
如何取主键字段名称及字段类型--得到主键字段名
1: SELECT TABLE_NAME,COLUMN_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE TABLE_NAME<>'dtproperties'
2: EXEC sp_pkeys @table_name='表名'
3: select o.name as 表名,c.name as 字段名,k.colid as 字段序号,k.keyno as 索引顺序,t.name as 类型
from sysindexes i
join sysindexkeys k on i.id = k.id and i.indid = k.indid
join sysobjects o on i.id = o.id
join syscolumns c on i.id=c.id and k.colid = c.colid
join systypes t on c.xusertype=t.xusertype
where o.xtype = 'U' and o.name='要查询的表名'
and exists(select 1 from sysobjects where xtype = 'PK' and parent_obj=i.id and name = i.name)
order by o.name,k.colid