EN一般来说，如果在单线程环境下进行字符串操作，并且不需要频繁修改字符串，可以使用String类。如果需要...
col4 varchar(500));因为indexed key size的限制是1700, 所以create index ind_t1 on table1(col1, col2,col3)没有问题,因为col1+col2+col3=1500<1700,但是create index ind_t2 on table1(col1, col2,col3,col4)有问题,因为col1+col2+col3+col4=2000>1700,但是我们可以这样create index ind_...
Transact-SQL 语法约定 语法 适用于 SQL Server、Azure SQL 数据库和 Azure SQL 托管实例的语法 syntaxsql 复制 CREATE [ UNIQUE ] [ CLUSTERED | NONCLUSTERED ] INDEX index_name ON ( column [ ASC | DESC ] [ ,...n ] ) [ INCLUDE ( column_name [ ,...n ] ) ] [ WHERE <filter_predica...
SQL Server、Azure SQL Database、Azure SQL 受控執行個體的語法syntaxsql 複製 CREATE [ UNIQUE ] [ CLUSTERED | NONCLUSTERED ] INDEX index_name ON ( column [ ASC | DESC ] [ ,...n ] ) [ INCLUDE ( column_name [ ,...n ] ) ] [ WHERE <filter_predicate> ] [ WITH ( <relational...
Include nonkey columns in a nonclustered index to avoid exceeding the current index size limitations of a maximum of 32 key columns and a maximum index key size of 1,700 bytes (16 key columns and 900 bytes prior to SQL Server 2016 (13.x)). The Database Engine doesn't consider nonkey...
Applies to:SQL ServerAzure SQL DatabaseAzure SQL Managed Instance This article describes how to create indexes on a view. The first index created on a view must be a unique clustered index. After the unique clustered index has been created, you can create more nonclustered indexes. Creating ...
CREATE ROLE (Transact-SQL) CREATE ROUTE (Transact-SQL) CREATE RULE (Transact-SQL) CREATE SCHEMA (Transact-SQL) CREATE SERVER AUDIT (Transact-SQL) CREATE SERVER AUDIT SPECIFICATION (Transact-SQL) CREATE SERVICE (Transact-SQL) CREATE SPATIAL INDEX (Transact-SQL) ...
CREATE ROLE (Transact-SQL) CREATE ROUTE (Transact-SQL) CREATE RULE (Transact-SQL) CREATE SCHEMA (Transact-SQL) CREATE SERVER AUDIT (Transact-SQL) CREATE SERVER AUDIT SPECIFICATION (Transact-SQL) CREATE SERVICE (Transact-SQL) CREATE SPATIAL INDEX (Transact-SQL) ...
Create a primary XML index Create a secondary XML index See also Applies to: SQL Server Azure SQL Database Azure SQL Managed Instance This article describes how to create primary and secondary XML indexes. Create a primary XML index To create a primary XML index, use the CREATE INDEX (...
不能使用 ALTER INDEX 语句进行更改。 若要更改非聚集索引,必须先删除该列存储索引,然后重新创建它。 可以使用 ALTER INDEX 禁用并重新生成列存储索引。 不能使用 INCLUDE 关键字创建。 不能包括用来对索引排序的 ASC 或 DESC 关键字。 根据压缩算法对列存储索引排序。 排序将抵销许多性能优势。 在 Azure Synapse...