IF EXISTS(SELECT * FROM sys.Tables WHERE name='stu_info') DROP TABLE stu_infoGoCreate table stu_info(stu_id int identity(1,1),name nvarchar(20)not null,birthday date null, sex nvarchar(2)null,addres nvarchar(20)null, mark
if object_id('student', 'U') is not null drop table student go create table student( sno varchar(20) not null , sage decimal not null, sname varchar(20) ) go create nonclustered index stu_index on student(sno) go if(object_id('person', 'U') is not nu
SQL Server 创建唯一约束sql语句 语句示例: 在创建表是时同时创建, 创建id,name,sex三个字段的唯一索引 create table t1( id int primary key,name varchar(50) not null,sex int not null,constraint un_id_time unique(id,name,sex)) 另下一种写法 create unique index u_index on table(id,name,sex)