我们很多程序员认为临时表非常危险,因为临时表有可能被多个连接所共享.其实在SQL Server中存在两种临时表:局部临时表和全局临时表,局部临时表(Local temp table)以#前缀来标识,并且只能被创建它的连接所使用.全局临时表(Global temp table)以##前缀来进行标识,并且可以和其它连接所共享. 局部临时表 局部临时表不能够...
IF OBJECT_ID(N'#Temp_Table', N'U') IS NOT NULL DROP TABLE #Temp_Table; GO -- 临时表查询 SQL Server 2016 (13.x) SP2 和更高版本。 SELECT * INTO #Temp_Table FROM Students WHERE Id > 1; GO -- SELECT INTO 创建永久表 SQL Server 2016 (13.x) SP2 和更高版本。 IF OBJECT_ID(N...
局部临时表(Local temp table)以#前缀来标识,并且只能被创建它的连接所使用.全局临时表(Global temp table)以##前缀来进行标识,并且可以和其它连接所共享.局部临时表局部临时表不能够被其它连接所共享的原因其实是在SQL Server 2000中自动为局部临时表的表名后面加上了一个唯一...
可以通过 SQL Server Management Studio (SSMS) 或运行系统存储过程sp_addlinkedserver(如以下示例所示)创建链接服务器。 SQL DECLARE@RCINT;DECLARE@serverNVARCHAR(128);DECLARE@srvproductNVARCHAR(128);DECLARE@providerNVARCHAR(128);DECLARE@datasrcNVARCHAR(4000);DECLARE@locationNVARCHAR(4...
CREATE [ OR ALTER ] FUNCTION [ schema_name. ] function_name ( { @parameter_name [ AS ] [ type_schema_name. ] parameter_data_type [ NULL ] [ = default ] } [ , ...n ] ) RETURNS TABLE <clr_table_type_definition> [ WITH <clr_function_option> [ , ...n ] ] [ ORDER ( <...
CREATE [ OR ALTER ] FUNCTION [ schema_name. ] function_name ( { @parameter_name [ AS ] [ type_schema_name. ] parameter_data_type [ NULL ] [ = default ] } [ , ...n ] ) RETURNS TABLE <clr_table_type_definition> [ WITH <clr_function_option> [ , ...n ] ] [ ORDER ( <...
-- Table creation logicCREATETABLE#temptable ([col1] [int]NOTNULLprimary key,[col2] [int]NULL, [col3] [int]NULL,[col4] [varchar](50)NULL)DECLARE@tablevariableTABLE([col1] [int]NOTNULLprimary key,[col2] [int]NULL, [col3] [int]NULL,[col4] [varchar](50)NULL,indexIX_col2(col...
CREATE PROC [dbo].[ScriptCreateTableKeys] @table_name varchar(50) AS BEGIN SET NOCOUNT ON --Note: Disabled keys and constraints are ignored --TODO: Drop and re-create referencing XML indexes, FTS catalogs DECLARE @crlf CHAR(2) SET @crlf = CHAR(13) + CHAR(10) DECLARE @version CHAR(4...
('street', address.street,'number',10)); >SELECTmyvar, address; 12 {"street":"Grimmauld Place","number":10}-- Drop a variable>DROPTEMPORARYVARIABLEmyvar; >DROPTEMPORARYVARIABLEIFEXISTSaddress;-- Use the IDENTIFIER clause with a variable>DECLAREview='tempv'; >CREATEORREPLACETEMPORARYVIEW...
If you do not create indexes that support the queries that are issued against your server, the performance of your application suffers as a result. However, if you have too many indexes, the insert and update performance of your application suffers. You have to find a balance between the ...