in -- 查找id 等于1或4或6 select * from info where id in (1,4,6); -- 查找id 在depart表中存在的id select * from info where id in (select id from depart); 1. 2. 3. 4. not in -- 查找id不等于1或4或6 select * from info where id not in (1,4,6); 1. 2. exists -- ...
Uniqueifier details in SQL ServerArticle 02/16/2018 This is a follow up post for <https://blogs.msdn.microsoft.com/psssql/2018/02/16/uniqueifier-cons…ns-and-error-666/>, for the ones that want to delve into the subject.First a quick background on uniqueifiers......
Applies to: SQL Server 2016 (13.x) and later Azure SQL Database Azure SQL Managed InstanceYou can create a unique constraint in SQL Server by using SQL Server Management Studio or Transact-SQL to ensure no duplicate values are entered in specific columns that don't participate in a primary...
normal:表示普通索引 unique:表示唯一的,不允许重复的索引,如果该字段信息保证不会重复例如身份证号用作索引时,可设置为unique full textl: 表示全文搜索的索引。 FULLTEXT 用于搜索很长一篇文章的时候,效果最好。用在比较短的文本,如果就一两行字的,普通的 INDEX 也可以。 总结,索引的类别由建立索引的字段内容特...
latest build for SQL Server 2016 Latest cumulative update for SQL Server 2014 Status Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. More i...
Applies to: SQL Server 2016 (13.x) and later versions Azure SQL Database Azure SQL Managed Instance SQL database in Microsoft Fabric You can create a unique constraint in SQL Server by using SQL Server Management Studio or Transact-SQL to ensure no duplicate values are entered in specific ...
You can create a unique constraint in SQL Server by using SQL Server Management Studio or Transact-SQL to ensure no duplicate values are entered in specific columns that don't participate in a primary key. Creating a unique constraint automatically creates a corresponding unique index. Note For ...
latest build for SQL Server 2016 Latest cumulative update for SQL Server 2014 Status Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. More in...
(1)Hash 索引仅仅能满足”=”,”IN”和”<=>”查询,不能使用范围查询。 由于Hash 索引比较的是进行 Hash 运算之后的 Hash 值,所以它只能用于等值的过滤,不能用于基于范围的过滤,因为经过相应的 Hash 算法处理之后的 Hash 值的大小关系,并不能保证和Hash运算前完全一样。
SQL数据库的基础操作 一,认识SQL数据库 美国Microsoft公司推出的一种关系型数据库系统。SQLServer是一个可扩展的、高性能的、为分布式客户机/服务器计算所设计的数据库管理系统,实现了与WindowsNT的有机结合,提供了基于事务的企业级信息管理系统方案。 其主要特点如下:...