create table Employee (
            ID int not null primary key,
            Name nvarchar(4),
            Credit_Card_ID varbinary(max)); --- 小心这种数据类型。
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ALTER TABLE table_name ADD CONSTRaiNT cons_name priamry KEY(columnname ASC|DESC,[.....]) WITH (drop_existing = ON);
ALTER TABLE employee ADD CONSTRAINT pk_for_employee PRIMARY KEY CLUSTERED (id);
go 

execute sp_helpindex @objname = 'Employee';
go

drop index Employee.PK__Employee__3214EC277D95E615;
go

create clustered index ix_name on table_name(columnName ASC|DESC[,......]) with (drop_existing = on);
create clustered index ix_clu_for_employee_ID on Employee(ID);
go

create index ix_com_Employee_IDName on Employee (ID,Name)with (drop_existing = on);

create index ix_com_Employee_IDCreditCardID on Employee(ID,Credit_Card_ID);

create index index_name on table_Name (columnName ASC|DESC[,......]) include(column_Name_List)with (drop_existing = on);
create index ix_cov_Employee_ID_Name on Employee (ID) include(Name);
go

create unique index index_name on table_name (column ASC|DESC[,.....])with (drop_existing = on);

insert into Employee(ID,Name) values(1,'AAA'),(1,'BBB');

create unique index ix_uni_Employee_ID on Employee(ID);
go -- 可以想到因为ID有重复，所以它创建不了。

create unique index ix_uni_Employee_ID on Employee(ID);
go

insert into Employee(ID,Name) values(1,'AAA'),(1,'BBB');
go

create index index_name on table_name(columName) where boolExpression;
create index ix_Employee_ID on Employee(ID) where ID>100 and ID< 200;
go