Temporary Tables And Table Variables In SQL 基本常识 1. 局部临时表(#开头)只对当前连接有效,当前连接断开时自动删除 2. 全局临时表(##开头)对其它连接也有效,在当前连接和其他访问过它的连接都断开时自动删除 3. 临时表就像普通表一样,它可以做索引等等 4. 临时表存在 tempdb database, 表变量存在 memory...
Step 1. To create a table variable, the appropriate syntax involves using the DECLARE statement in conjunction with the TABLE. Syntax for Declaring a Table Variable. DECLARE @TableName TABLE ( Column1 DataType PRIMARY KEY, -- Primary key example Column2 DataType, Column3 DataType );...
我们不能使用语句创建表变量 select * into @tableVariableName 但是我们可以使用Create table语句和语句创建临时表 select * into #tempTableName 在SQL Server 2008之后我们可以将表变量作为参数传递给存储过程。 但是我们不能把临时表作为参数传递给存储过程。 我们可以在 UDF(用户定义函数)内使用表变量,但不能...
Temporary Table vs Table Variable There are two ways to create a temporary table: 1. ‘On the fly’ by designating an “INTO” clause after a SELECT statement and before a FROM clause: 2. The same way as defining an actual table by using the following syntax: ...
表变量:@T1 临时表vs表变量:可见性,持久性,性能(具体见下表) 临时表有统计信息可以支持优化 表变量不需要重新编译 Table 2-4: Comparison Summary 即使你拥有人人羡慕的容貌,博览群书的才学,挥之不尽的财富,也不能证明你的强大,因为心的强大,才是真的强大。
The variable will not exist after the procedure exits. There will be no table to clean up with a DROP statement. We cannot create a non-clustered index on a table variable, unless the index is a side effect of a PRIMARY KEY or UNIQUE constraint on the table. It can only have indexes...
SQL Server Temporary Table & Table Variable (临时表和表变量),参考:在数据库中临时表什么时候会被清除呢TemporaryTablesAndTableVariablesInSQL基本常识1.局部临时表(#开头)只对当前连接有效,当前连接断开时自动删除2.全局临时表(##开头)对其它连接也有效,在当前
7. Table variables are the only way you can use DML statements (INSERT, UPDATE, DELETE) on temporary data within a user-defined function. You can create a table variable within a UDF, and modify the data using one of the above statements. This is not possible with temp tables....
1-- Example of using a temporary table instead of a table variable 2CREATE TABLE #TempTable (ID INT, Name NVARCHAR(50)); 3INSERT INTO #TempTable (ID, Name) VALUES (1, 'Sample'); 4SELECT * FROM #TempTable WHERE ID = 1; If using a temporary table is not feasible, use the USE ...
both will now contain the same "new value" string. But when we rollback the transaction, as you can see, the table-variable @T retained its value instead of reverting back to the "old value" string. This happened because, even though the table-variable was updated within the transaction,...